Shop Products
Houzz Logo Print
gwcoln

Miracle Gro Potting mix problems

COLN
10 years ago

This year I had to switch to all container gardening. I bought Miracle Gro Potting mix and filled all containers. I have to say I am terribly disappointed. I can't say any of the plants are really thriving as they did in the garden. The tomatoes have developed blight on their lower leaves, the chard refused to germinate in it, and the cukes came up but either died after their first leaves formed or like now are slowly dying without any cukes forming. Did anyone else have a problem with this mix or did I buy the five bags that were contaminated?

Comments (66)

  • johns.coastal.patio
    9 years ago

    I've used a number of potting soils, and even run the big mixer at a local arboretum.

    I guess I'm an optimist after that experience, I think there are more good mixes out there than bad.

    That said, I guess I accept that MG could have a "bad batch" here and there. They'd certainly be on guard against it, to protect their reputation, but they can't test all their inputs in every batch .. especially against something sneaky, like a "cide" of some kind sprayed on an input of bark or peat.

    One thing I do like to remind people is that in many regions there are suppliers for greenhouses which have potting soil available in bulk. Where available I'd think those would both be reliable and economical.

    For instance, a compost, peat, and pumice mix from www.compostoregon.com, a mere $48 per cu yd, or $1.77 cu ft.

  • the_yard_guy
    9 years ago

    Some of the problems posted in this thread gave me the motivation to figure out how to make my own soil mixes.

    I have seen many containers filled with MG or other brands of peat-based potting soil that retain so much water that plant roots actually rot and die in the bottom of these containers.

    Last year a friend complained that his tomato plants had mostly yellow leaves and were not producing anything. Turns out that when he dumped the soil at the end of the season the peat-based potting soil was completely waterlogged. Most of the containers were saturated with water and the roots of the tomato plants looked really bad.

    A few years earlier I bought a 3 or 4 foot tall sugar maple tree from a big box store at end of season sale for a very small cost. The tree was in bad shape, looking very droopy and with few healthy leaves. I removed it from the container and the soil was a mix of peat and sand, completely soaked with water. The soil even smelled bad. I planted the tree in the ground that fall and gave it some TLC for a few months and the tree rebounded into a fine and healthy tree.

    I'm not saying all peat-based soils are bad and should not be used. Some people swear by them and others like the convenience of buying pre-made soil without the extra trouble of screening bark or finding perlite or Turface. I simply believe there are better alternatives and prefer to use them whenever possible.

    TYG

  • johns.coastal.patio
    9 years ago

    Commercial growers, including greenhouse growers of produce (most closely matching my interest as a container vegetable grower), use all kinds of things, some peat based, some pine bark based, some compost based, etc., etc.

    This makes me think the key is matching soil to crop, and to practices.

  • Pyewacket
    8 years ago
    last modified: 8 years ago

    I've used MG off and on for 50 years. I have never had gnats.

    If it or any other decent bagged mix - all potting mixes NOT being equal - was "death" to your plants, you were most likely not watering properly.

    I used to use 50/50 peat and coarse vermiculite. When I couldn't get coarse vermiculite any more, I went to 50/50 peat and MG garden soil. Not potting mix - the actual garden soil. A lot of other stuff sold as "garden soil" is black gunk with sand in it.

    Currently I'm doing 1:2:3 Growstone GS2, bark, and peat, but I still use slightly amended bagged soil for some things as this mix is just to expensive to be using on garden plants - and garden plants in containers of peat-and-good soil has always worked fine for me.

    I grow in large containers. If you try a peat blend in a 5 gallon container in this particular climate, you will quickly end up with sludge in the bottom and the top all dried out - this is a desert. It is hot and dry. You could fix that to a certain extent by wicking out the bottom - but in my mind, 5 gallon buckets are too small for most everything anyway, so just get properly sized containers to start with and things will work out much better. They do for me.

    I tried gritty last year - and tried, and tried, and tried. It was problematic to water, dried out very quickly in the desert heat and arid conditions, had a lot of pH problems, which caused problems with fertility. I had to float the plants to water them thoroughly as I don't have a misting system and am unable (and frankly unwilling) to go about watering 30 plants every day with a hand mister.

    After talking to a soil scientist at the local university, where they use a gritty type mix for cacti and native plants, she and I both concluded that gritty mix is not perfect, requires a certain way of handling, and should not be used willy-nilly for every plant.

    Its not that it CAN'T work - it can. But you have to be willing and able to do a LOT of extra work, and I am neither willing nor able.

    If you're willing to repot appropriately, you have good watering practices to start with, it is far, FAR easier to use a slightly amended bagged mix or a peat blend of your own devising. Cornell has several good mixes to suggest - and they're not exactly idiots over there.

  • John
    8 years ago
    last modified: 8 years ago

    "I tried gritty last year - and tried, and tried, and tried. It was problematic to water, dried out very quickly in the desert heat and arid conditions, had a lot of pH problems, which caused problems with fertility."

    This is puzzling given that (1) being a custom mix, gritty can easily be mixed at different ratios to become (much) more water retentive -- in this case, by increasing the Turface proportion, and (2) gritty ingredients mixed at 1:1:1 has a PH of roughly 6.0, optimal for most flora. In the previous example of increasing Turface, its pH of 6.2 would have little effect on total substrate pH.

    I'm also perplexed by the amount of watering you hard to do. Gritty's drainage and total porosity are (in my opinion) its biggest allures, but its surprisingly water retentive as well. Aside from Turface, the micropores of pine and fir bark allow it to hold meaningful amounts of water. This study showed that when bark was substituted for peat in equal proportions, plants went longer before wilting in most cases: http://www.hriresearch.org/docs/publications/JEH/JEH_1987/JEH_1987_5_2/JEH%205-2-89-92.pdf, concluding "[with bark,] less frequent irrigation may be needed in contrast with media composed of components other than pine bark."

    And, of course, there's the inclusion of Turface which holds its own weight in water.

    I agree that more work is required upfront, primarily the tracking down of materials. It's certainly not for those who want to set it and forget it. For those, I agree that amending a bagged mix is easier.

    ------------

    "but in my mind, 5 gallon buckets are too small for most everything anyway, so just get properly sized containers to start with and things will work out much better."

    I hate to become the umpteenth evangelist of gritty/5:1:1 because there are certainly enough of them, but I'll point out that when you have a substrate that's superior in drainage, air-filled porosity, and water holding capacity (and compaction resistance, and CEC, and... yadda yadda yadda), you're no longer limited by container size. The majority of mine are in fact 5 gallon containers.

  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago
    last modified: 8 years ago

    I agree with John. When someone assumes that all soils ALLOW the grower to water correctly, it's easy to make a case for that soil. E.g., if you ASSUME that MG et al allow you to water correctly, why aren't the more experienced growers using MG et al with great success? The answer is, because soils based on fine particulates have inherent limitations that aren't easily overcome, one of which is the inability to water correctly because of excessive water retention.

    Technically, you can't effectively amend MG et al because it takes a larger fraction of coarse material than the MG fraction to make a notable difference. When there is a larger fraction of another ingredient (pine bark, e.g.) , MG then becomes the amendment.

    People choose the perspective that best serves their purpose when discussing soils like the gritty mix and the 5:1:1 mix. Some growers will demonstrably hate them because they involve an up front effort, even if they offer a substantial cost savings over what is commercially available. That's fine - no one really cares if someone doesn't want to make the effort (or can't), but that one person can't/won't make the effort has absolutely no bearing on what the soil has to offer plants, which is what I'm interested in. WHY these soils are far superior to MG et al, amended or not, is easy to explain, and easy to see once given a fair trial.

    Whether or not a person decides to make the effort to build these soils is a personal decision. I wouldn't think of using a bagged soil - too expensive and generally poor quality. Convenience is a distant consideration for me when it comes to providing the cultural conditions that allow the plants I grow to realize as much of their genetic potential as possible - but that's just ME. I do know, based on the results I get from the soils I MAKE, if plants had a say they would opt for something less like mud than MG et al.

    Al

  • bragu_DSM 5
    8 years ago

    amen, al.

  • Nil13 usda:10a sunset:21 LA,CA (Mount Wash.)
    8 years ago

    How did you determine you were having pH problems with the grotty mix zen?

  • Rosie1949
    8 years ago

    I have read this entire page and find it interesting as far as Miracle Gro potting soil.

    I have used it for years on my indoor plants only. All are houseplants. Not many seeds. But I start cuttings and repot all types of plants and even though I use MG I always end up amending it with perlite, vermiculite or sometimes course sand. It depends on what I am potting up. I rarely use it straight out of the bag. But then again I can't follow a recipe the way it is written without changing it! lol.

    I don't have any complaints so far. There was a point I had an episode with those pesky gnats, but I changed MY watering habit with that plant and they went away!

    I have used other bags of "potting soil" and they were nothing but muck, especially when wet. I had to amend them alot more than the MG, to get it to be usable until it was gone. These are the 40lb bags of POTTING soil, not TOP soil from Kmart, Walmart, and other big box stores.

    I think alot that happens is due to the enviornment. 2 identical plants living in 2 different sections of the country (or even county for that matter) possibly 2 different sets of issues as far as soil, watering and temperature. Doesn't make the potting mix bad you just have to amend it to suit what you are growing in the climate you have! Adjustment. I do believe that is the key.

    I still use the Miracle Grow because the way I handle it, it works for me. No matter what anyone else uses you have to be happy with how it works for you. The results. Use what is best for your climate no matter what it is named.

    I bet a nickel some people will like those 40lb bags that I don't like! That's ok, they just didn't work out for me!

    All of my comments are strictly my own opinion based on my growing habits over the last 50 years or so.

    Good luck with what ever you choose, but amend it to your growing conditions! Rosie



  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago

    Hi, Rosie. If one assumes Miracle-Gro soils and other soils based on fine particulates CAN effectively be 'amended' w/o ending up with a VERY large fraction of coarse material, so much coarse material that the MG actually ends up being a very small fraction of the O/A mix, they're already off the rails. You can't add 10, 20, even 50% perlite or vermiculite (wouldn't use it) and expect any significant difference in drainage, aeration, or ht of the perched water table. I can make that statement because what happens in soils re water retention is based on particle size and particle porosity, which makes things extremely predictable.

    If a grower likes MG soils, that's fine, and I wouldn't try very hard to change that person's mind. I'm more interested in making sure others aren't left with the impression that it's a simple matter to 'amend' water retentive soils. It's not, and soils based on fine particulates (like MG et al) simply cannot offer equal opportunity for plants to realize their genetic potential when compared to soils based on much coarser ingredients.

    Our opinions differ. The topic of this and similar threads (Problems) are seen routinely when discussing soils based on fine particles, accolades rarely.


    Al

  • Rosie1949
    8 years ago

    Well, I am glad our opinions differ. That is how everyone learns. Not that is changes anyone's mind for sure, but at least if you are looking for information about something, it gives you "food for thought". That is why I am reading this thread with so much interest.

    Yes I have used MG for years. And my system works for me. For now. As I said, I mix soil every time I repot. I go by feel, sight and what happens when I water. Especially after I let it go dry. How does it drain, how does it soak up and how does the plant respond and grow to it etc.

    I use it as a base and yes, I amend it with lots of different things depending on the type of plant I am dealing with.

    I don't want to use garden soil and "cook" it in my oven. I don't have greenhouses and nurseries that can supply me with "their" favorite mix. So I "start" with MG and go from their. And as I said I have tried other "potting soil". Just didn't do well for me even if I did amend it.

    But I am still interested in reading this thread even though I don't understand everything. I will get it eventually. Bear with me and thanks for all of the various opinions. I will keep reading. Rosie

  • drew51 SE MI Z5b/6a
    8 years ago

    I too tend to favor fine soils, just because I have had much better luck with them. Also stuff like bark that is not composted has been a problem, not with all plants, but heavy feeders show problems with uncomposted bark. I have made numerous mixes the last two years. It was fun, I learned a lot. Now though time is becoming an issue, so I'm going back to commercial potting soil till I have more time again. My choice is Fafard as it is the closet to my mixes that I liked. Fafard is about 60% bark. My best mixes were 50%, close enough. I will still amend the soil, just not start from scratch. It will be 50% bark once done.


  • Rosie1949
    8 years ago

    Hi Drew! you are in SE Mi???? Near Monroe???? What do you grow??? As far as indoor plants if you don't mind me asking???

    Really hate to admit this, but if the bark is too large for my liking (no matter what the mix), I pick it out and save it for when I am potting a catus or succulent. I don't get it that often, but I remember I once bought a bag of cactus soil and I was not impressed. I can't remember why I didn't like it, but I only remember that I didn't.

    I have heard Fafard mentioned before, in the african violet threads (I grow a lot of them!). Where do you buy that? Anybody got any issues with it? I have never seen it, let alone used it. Rosie


  • jane__ny
    8 years ago

    Hi Rosie, nice to meet you.


    I mix my MG like you do. I'm an orchid grower so always have large bags of bark on hand and mix my own. I dump a bag of MG into a wheel barrow and add other stuff to loosen it up.


    I live in Florida now but most of my past growing was in NY. I never had a problem with Miracle Gro but I always added things to it. In NY I had many large houseplants (other than orchids) and mixed the soil according to how much moisture retention my plants required. I had good sun/light and my plants grew well. I have always been a bad waterer and had to work around that. I tend to underwater.


    I grew a large ficus (12ft), Plumerias, Pachira, citrus, etc. All grew well. I brought the Plumerias and Pachira with me to Florida. Plumies went in the ground and are great but the Pachira is still potted. I started a thread above about my recent repot.


    I have bought bark mulch from Walmart (Timberland), quite inexpensive for a large bag, $2.00+ (can't remember but know its cheap for a large bag. I have always used that to mix with the Miracle Gro for the large trees. I always add some perlite. No problems. Miracle Gro is inexpensive if you watch the sales. I always stock up on the large bags. I use it for seedlings and cuttings also.


    Anyway, its always good to get different methods of growing plants. One can experiment and learn as they move along. So much is dependent on the environment they grow in and their watering habits. It is the same growing orchids. There is no 'one size fits all.' You have to deal with how people grow, where they live and grow and how much time they have for their plants.


    It is the best way to advise someone as you can't change someones lifestyle. You deal with what the person can manage.

    Good luck,

    Jane



  • jane__ny
    8 years ago

    Hi Rosie, nice to meet you.


    I mix my MG like you do. I'm an orchid grower so always have large bags of bark on hand and mix my own. I dump a bag of MG into a wheel barrow and add other stuff to loosen it up.


    I live in Florida now but most of my past growing was in NY. I never had a problem with Miracle Gro but I always added things to it. In NY I had many large houseplants (other than orchids) and mixed the soil according to how much moisture retention my plants required. I had good sun/light and my plants grew well. I have always been a bad waterer and had to work around that. I tend to underwater.


    I grew a large ficus (12ft), Plumerias, Pachira, citrus, etc. All grew well. I brought the Plumerias and Pachira with me to Florida. Plumies went in the ground and are great but the Pachira is still potted. I started a thread above about my recent repot.


    I have bought bark mulch from Walmart (Timberland), quite inexpensive for a large bag, $2.00+ (can't remember but know its cheap for a large bag. I have always used that to mix with the Miracle Gro for the large trees. I always add some perlite. No problems. Miracle Gro is inexpensive if you watch the sales. I always stock up on the large bags. I use it for seedlings and cuttings also.


    Anyway, its always good to get different methods of growing plants. One can experiment and learn as they move along. So much is dependent on the environment they grow in and their watering habits. It is the same growing orchids. There is no 'one size fits all.' You have to deal with how people grow, where they live and grow and how much time they have for their plants.


    It is the best way to advise someone as you can't change someones lifestyle. You deal with what the person can manage.

    Good luck,

    Jane



  • jane__ny
    8 years ago

    Hi Rosie, nice to meet you.


    I mix my MG like you do. I'm an orchid grower so always have large bags of bark on hand and mix my own. I dump a bag of MG into a wheel barrow and add other stuff to loosen it up.


    I live in Florida now but most of my past growing was in NY. I never had a problem with Miracle Gro but I always added things to it. In NY I had many large houseplants (other than orchids) and mixed the soil according to how much moisture retention my plants required. I had good sun/light and my plants grew well. I have always been a bad waterer and had to work around that. I tend to underwater.


    I grew a large ficus (12ft), Plumerias, Pachira, citrus, etc. All grew well. I brought the Plumerias and Pachira with me to Florida. Plumies went in the ground and are great but the Pachira is still potted. I started a thread above about my recent repot.


    I have bought bark mulch from Walmart (Timberland), quite inexpensive for a large bag, $2.00+ (can't remember but know its cheap for a large bag. I have always used that to mix with the Miracle Gro for the large trees. I always add some perlite. No problems. Miracle Gro is inexpensive if you watch the sales. I always stock up on the large bags. I use it for seedlings and cuttings also.


    Anyway, its always good to get different methods of growing plants. One can experiment and learn as they move along. So much is dependent on the environment they grow in and their watering habits. It is the same growing orchids. There is no 'one size fits all.' You have to deal with how people grow, where they live and grow and how much time they have for their plants.


    It is the best way to advise someone as you can't change someones lifestyle. You deal with what the person can manage.

    Good luck,

    Jane



  • jane__ny
    8 years ago

    Hi Rosie, nice to meet you.


    I mix my MG like you do. I'm an orchid grower so always have large bags of bark on hand and mix my own. I dump a bag of MG into a wheel barrow and add other stuff to loosen it up.


    I live in Florida now but most of my past growing was in NY. I never had a problem with Miracle Gro but I always added things to it. In NY I had many large houseplants (other than orchids) and mixed the soil according to how much moisture retention my plants required. I had good sun/light and my plants grew well. I have always been a bad waterer and had to work around that. I tend to underwater.


    I grew a large ficus (12ft), Plumerias, Pachira, citrus, etc. All grew well. I brought the Plumerias and Pachira with me to Florida. Plumies went in the ground and are great but the Pachira is still potted. I started a thread above about my recent repot.


    I have bought bark mulch from Walmart (Timberland), quite inexpensive for a large bag, $2.00+ (can't remember but know its cheap for a large bag. I have always used that to mix with the Miracle Gro for the large trees. I always add some perlite. No problems. Miracle Gro is inexpensive if you watch the sales. I always stock up on the large bags. I use it for seedlings and cuttings also.


    Anyway, its always good to get different methods of growing plants. One can experiment and learn as they move along. So much is dependent on the environment they grow in and their watering habits. It is the same growing orchids. There is no 'one size fits all.' You have to deal with how people grow, where they live and grow and how much time they have for their plants.


    It is the best way to advise someone as you can't change someones lifestyle. You deal with what the person can manage.

    Good luck,

    Jane



  • Rosie1949
    8 years ago
    last modified: 8 years ago

    Hi Jane! Thanks and nice to meet you 4 times over! lol

    As far as orchids go, you are so right about no one size fits all! There is only one thing that I disagree with on Orchid tags. And that has to do with watering with an ice cube or 2. It is similar to giving a kid (or adult) a teaspoon of food and calling it a meal!!!! Nuff said.

    Have you ever used a little smattering of MG or other potting soil when you mix up your orchid mix? I have thought about doing it but haven't yet. After all, in the wild wouldn't dirt/soil/leaves etc blow into the area where they are nestled? Just a thought I ponder.

    My go to mix is orchid bark and just some shredded spaghnum. Then I soak the entire repotted plant for about 1/2 hour to let the bark get good and soaked. Then my orchid is good for about a week. At least in the winter. They (believe it or not) don't dry out as fast in the summer and I have them out on my deck where they simply go nuts!!!!!!

    Actually you sound like me when it comes to potting and repotting plants! I do it kinda by look and "feel" of the mix. Gut instinct. I know this is not very scientific but it works for me! Rosie

  • jane__ny
    8 years ago

    OMG! What the heck happened, lol!


    You are right about orchids. I do not use any potting soil with them. Certain orchids get very small bark, some get a mix with sphagnam moss. Depends on the orchid and the growing environment. Nothing is cut in stone. You learn as you go along.

    I do soak the bark overnite or even up to a week (sometimes I forget its soaking). Never use ice cubes, lol.


    I moved from NY to Florida 3 yrs ago and still trying to relearn and 'unlearn' everything I learned for 50 yrs up north. Not easy at all. Totally different growing environment.


    Just keep plugging away and learning. That's what growing is about. Learning your environment, your lifestyle and plants. There is no simple rule. You need to figure out what works well for you and your plants. Simple.


    Jane

  • Rosie1949
    8 years ago

    Well, Jane truer words were never spoken! Must be hard to re-learn and learn again! Good Luck!!!! Keep posting and let us know how it's going!!!! Rosie

  • Sans2014
    8 years ago

    Jane, take it from me you can grow most anything in Florida. I lived there for 7 years. Tomatoes corn not so good, but houseplants! Not to mention oranges coconuts pineapples, LOL! Yes it is different but gives almost everyone a green thumb! Enjoy

    Fred

  • Rosie1949
    8 years ago

    Hey Fred! Yeah, there are a few plants I would love to have that just plain grow well in Fla. They are virtually unobtainable here! Rosie

  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago

    Plants are genetically programmed to prefer a very narrow range of cultural conditions before preference becomes tolerance, and those predispositions do not change because the plant's geographical location changes or because grower A's watering habits are different than grower B's. Plants might not even marginally tolerate a soggy soil better in hot/dry/windy locations because waterlogged soils support higher root temperatures and inhibit water uptake; but even if a soggy soils DID perform marginally better in hot/dry/windy than the same soil elsewhere, that can't be taken as something the plant prefers simply because it tolerates it. That a soil doesn't remain soggy for quite as long in hotsville as it does in coldsville means only that it doesn't remain limiting for quite as long - not a particularly laudable trait. More often than not, the cure for issues related to wilting or the inability of plants to take up an adequate volume of water lies in LESS water in the rhizosphere, not more.

    If Miracle Grow soil was a GOOD soil, we'd be able to water plants growing in it correctly. Fora are rife with sad stories about MG et al. That we feel we need to 'amend' it with bark and perlite in order to fix its deficiencies directly supports the thought that even people who praise it won't use it as it comes from the bag. When you amend it with a good measure of bark and perlite, that sounds an awful lot like the 5:1:1 mix, with the only question being how much bark is being added to turn a product that has serious inherent issues into something useable.

    People choose to use a particular soil for a number of reasons, and not all are pivotal on the soil's ability to provide what the plant prefers.

    Al

  • jane__ny
    8 years ago

    Hi Al. I totally agree with you. I would never recommend using Miracle Gro by itself. I only use it because it is easy to buy and amend. Sort of like making a cake. When you bake long enough, you learn ways to move away from a recipe without killing the cake. Different flours, different leavening. Recipes calling for buttermilk can be bypassed by souring regular milk.


    Purists might notice the difference, but most people aren't purists. MG is not great. But its handy and inexpensive. Mixed with bark and perlite works for me. Maybe not for purists.


    I just can't get crazy over potting mixes. I deal with a lot of orchids and play with mixes to fit the individual plant. In Florida, very high light levels, humidity, heat and moisture is a problem. So, I fiddle around trying to satisfy the outdoor conditions for my plants. My dirt plants in pots, require quite a bit of fiddling.


    It is very dry over the winter with little rainfall. Summer is another story. Daily rains, thunderstorms and very high humidity. Fungal, insects and wind are part of life here.


    Living and growing in NY was different. Dry winter environment with much lower light levels. Outdoors during summer, still less intense light levels than Florida.


    I'm learning the 'curve' here. Light levels are intense and most houseplants explode with growth. The heavy rains, high humidity is something to contend with but I always felt that strong light encourages green growth which in turn, produces root growth and uptake of water. I've always been a believer in 'light.' Give a plant good light, it will grow in anything.


    I have no argument with a grit mix. I just choose to use a basic potting media amended to provide the moisture holding ability I seek. I need to use a potting mix which can be used in large containers that I can move physically. MG, perlite and small bark work very well for me. When I don't want the expense of using orchid bark, I buy the large bags of Timberland (Walmart). I do not screen (never found it necessary), I have never found any of my mixes to settle and have good root growth. At least to my eye!


    As you say, there are growers who grow for convenience, cost and laziness. I am definitely one of those and it works for me. I'm not embarrassed to say that, it is a fact of my life. If things turn sour, I might try something else. But after 50 yrs of gowing, I satisfied with my results. Tropical climate is a challenge, but I'm up for it. Keeps things interesting.


    Jane

  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago

    No one should be embarrassed about how they order their priorities, but when talking about media for container growth, it's important to have accurate information that can be used to make decisions about what's right for an individual. All in all, I'm not interested in what decisions someone makes about their soils (THAT would drive someone crazy) as I am in making sure they have the tools to decide and improve the ratio of effort:reward they get from the growing experience. The growers who want something they likely can't buy in a neat package are those I want to converse with. I'm quick to point to the limitations of soils like MG et al because it's important for growers to understand that these soils are as unlikely to offer optimal opportunities for plants in the deep south as they are on the Canadian border. I've always said these soils CAN effectively be used as an amendment to coarser materials to produce a very productive medium. You essentially do that, just not to the degree many others and I do, so we essentially embrace the same concept, but to different levels; and we both seem to agree that MG soils and others based on high % of fine ingredients, as they come from the bag, are inherently problematic.

    "... I always felt that strong light encourages green growth which in turn, produces root growth and uptake of water. I've always been a believer in 'light.' Give a plant good light, it will grow in anything." Root growth always precedes top growth, which is why the seed radicle is the first organ to emerge from the seed; this, even in view of the fact that all nutrition for the plant's beginning stages of life is contained in the seed cotyledons/endosperm. This makes all top growth dependent on precursory root growth; so it's not just a play on words when I say that strong light encourages root growth which in turn allows for additional top growth. All it takes to short circuit the cycle is a poor soil that inhibits root function, a limitation that comes to play regardless of light levels. I'm not discounting the critical importance of light levels to optimal growth/vitality, but light levels cannot 'make up' for poor soils any more than they can for poor nutrition or low temperatures.

    Al

  • Rosie1949
    8 years ago

    Hi Jane, like you I can't get nuts over potting mixes. I know what is available in my area to work with and that is that.

    I amend to suit my plants, my growing habits etc. and that works for me. At the end of the day that is all that matters. I don't have to add that much in amendments to make it "feel" the way I want it to either.

    Speaking of amendments,,,does anyone ever add fertilizer to their soil mix? I don't. Don't think I ever will, it was just a question that popped into my head.

    Well it is too bad no one can "pick" on something other than MG. [Would really love to see that list.] It works for me as a great base. I have used everything from cheap $2 bags to more expensive than MG. Don't know why, but I always go back to it! Good results the way I use it!

    BTW I am not a novice grower, I learned at Grandma's loooong before bagged soil! You have a plant to be repotted? Go to the garden and fill a pot with dirt. Yes that dreaded word dirt! But it was in the 50's. No bagged soil then. And guess what? It worked for grandma and thousands of others for many years. BUT they also buried their garbage (fertilizer, none of that came in a bottle for convenience!)

    Look how far we have come. Now it is called SOIL and boy everyone will get on you for saying dirt! Unless you are talking mud pies! lol.

    Good Growing to All whatever you use!!!!! If you are happy with the results then your train is still running on the rails!!!!! Rosie

  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago

    “It works for me” really says
    nothing about the comparative quality/value/efficacy of the method/product in question. It simply gives notice that the person using the statement is content with things
    as they are, leaving the door open wide to the possibility/probability there
    are other methods/products that might work much better that the
    method/product they hold to. No one is criticizing anyone's methodology or choices, and we already agree that people make choices for divergent reasons. If a grower is happy with the status quo, I'm glad for that grower and endorse whatever the growers choices are for him/herself, but that doesn't mean the endorsement extends to growers intent on improving their proficiency. Whenever I hear that MG et al based on fine materials are good and suitable on a stand-alone basis, I'll explain clearly why they are better choices and why suitability isn't related to geography or local conditions. This allows the grower to decide for themselves what compromises they would like to make, rather than beginning an endeavor from a compromised position for no reason other than a lack of information.

    We can only have a meaningful conversation about soils if it occurs from the perspective of the plant, because the conversation can then be very definitive. I always look at things as an advocate for the plant because variation in the grower's POV is endless and none of them can be said to be wrong. Unfortunately, our proficiency as growers is defined by how well we recognize and eliminate limitations that prevent our plants from realizing their genetic potential. We know with absolute certainty that perched water/soggy soils limit plants, and we can predict with a great deal of reliability which soils hold perched water and about how much. If a grower chooses to live with a limitation, it's neither right or wrong, but it remains a limitation just the same. I've always been about helping growers learn how to rid their growing experience of limitations, which is why a perspective that might encourage them to accept those limitations can be counted on to draw comment.

  • greenirene94
    8 years ago

    I am in a seemingly endless battle with mold gnats whose great great great grandparents literally flew out of the bag of Organic Miracle Grow potting soil I purchased indoors at WalMart 2 months ago. My established Plumeria,Cacti and Succulents are doing well in my new greenhouse-like loft space (massive skylights/all day Sun) thanks to soil topped with sand, pebbles and larger rocks, but the veggies I am trying to direct sow into appropriately sized pots seem to be getting taken out from below by an endless stream of gnat spawn despite ample sowing of BTI coated mosquito bits, sand and cinnamon (supposedly antifungal) sprinklings in the top layer. The adults have eschewed every liquid concoction trap I could conjure, they don't seem to mind digging around new sprouts saddled by growstone gnatnix, they're not off put by peppermint scented oils painted upon my planters. I belatedly employed yellow sticky traps with favorable results, but there aren't enough sticky traps in the world to fully eradicate these pests. I have been using a peroxide solution to try to knock out flies and larva between resowings and when seedlings are seemingly strong and stable... it's supposed to be good for the roots, maybe it makes them better tasting to the larva? (Lost an entire pot of true-leaved rainbow carrots overnight to suffocation via envirofriendly flying bug spray comprised of mint and rosemary oil and I barely used any). Should I bother attempting to sterilize the remaining soil in the oven? Replace it all (already spent more than desired trying to fix problem)? Bought a bag of Mosser Lee seed starter and some coconut husk seed pots.. thought I might restart some seeds in different medium (but leery it too will become infested) and plant the biodegradable pots in planters as planned once fully rooted and established.. I have a heat gun I've thought about using to sterilize in situ in the ceramic pots- any thoughts on that? I do not have a yard or outdoor space to work in at all, was thinking I could take affected planters after heat sterilizing moist soil by applying heat w/gun and stirring while tracking temp w/thermometer, applying fresh BTI and rewetting then leaving out of Sun (private storage area) and quarantined from newly planted seedlings, should give me a couple weeks to assess infestation state before seedlings are ready to be repotted.. none of this is ideal, wish I never bought the MG soil in the first place. help. me. p l e a s e

  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago

    The heavier the soil (the more water retentive) the more fervent the orgiastic frenzy of the resident fungus gnat population. The more airy the soil, the greater the quelling effect on their enthusiasm. Organic fertilizers like fish emulsion, and organic soil amendments, like meals (alfalfa, cottonseed, bone, blood, feather, .....) also put a fiendish grin on their faces as reveries of future bouts of procreation dance in their heads.

    Fungus gnats like wet soils and lots of organic matter that breaks down easily. Compost piles need to be turned, or organic acids are produced during anaerobic composting, and that's a problem. Turning the piles cost's money, so it's not uncommon for the "compost" used in commercial soils to be ground up while still far from finished. The result is a soil with a lot of carbohydrates to serve as food for gnats and other organisms that immobilize nitrogen.

    Gnats are more of a symptom of a soil that portends issues related to water retention than they are a problem, but they do feed on fine roots if populations are high enough.

    Soils that are based on coarse materials usually have no issues that involve fungus gnats - no matter how often you water them. That's because the top strata of the soil dries down quickly due to good gas exchange around/through the coarse particles. Add too much fine material to the coarse ingredients, and your exactly back in the place you started. Soils with more than 25% fine organic particles (peat, coir, compost, composted forest products, even topsoil with an organic fraction) are always going to have the potential for water retention and gnat issues because even if you have 1 part of peat (25%) to 3 parts of pine bark nor other coarse material, there will be enough fine material to completely fill all the large pores between soil particles. When this occurs, the drainage rate, aeration, and ht of the perched water table are the same as if you were growing in all fine material ..... which is why you can't effectively amend a fine soil by adding even adding a significant fraction of course material. The ratio of coarse to fine must be such that there is not enough fine material to clog up all the large air pores that plants like so much.

    I have a friend who receives international attention for the quality of her plumeria, she also grows adenium and a variety of succulents. I'll see if she'll let you know what she thinks. I grow in well-aerated soils that support little or no perched water. They require more frequent watering than water retentive soils, but it's easy to build a case around 'the more often a soil needs watering', the more potential it offers your plant' (to a point). I'm not usually prone to vagary like the last statement, but I can add plenty of qualification to frame it properly if anyone desires.

    Have you read this post about how water behaves in container media? It probably represents the largest step forward a container grower can take at any one time.

    Al

  • Sans2014
    8 years ago

    to rid your bag of fungus gnats, dry the soil out on some newspaper or such in the sun. That will stop the problem. Then prior to use re-wet the soil so it is not hydrophobic.

  • Loveplants2 8b Virginia Beach, Virginia
    8 years ago
    last modified: 8 years ago

    Hi Al,

    You give me more credit than I deserve for my growing abilities and my accomplishments... Thank you..but it is because of you and what I have learned that have made all my trees respond in their best way possible.

    i started with the basic understanding of how plants need proper aeration and proper gas exchange. I studied the concepts that are outlined In Your thread Container Soils- Water Retention XXII. http://forums2.gardenweb.com/discussions/2842847/container-soils-water-movement-and-retention-xxii?n=143

    I see people talking about using Miracle Grow and asking questions . Before I understood the basic concept on how proper mixes work, I would have been the one to grab a bag of this and use it. Fungus Nats as well as other problems were always an issue. Once I learned how to make my own mix, either the Gritty Mix which I use on a lot of my trees as well as the 5-1-1 on many trees as well. It became a very easy way to grow and my trees are very happy and healthy. The major change is proper aeration and little to no perched water that causes root problems. i just don't have rotting issues anymore with my well draining mix. The best place for a healthy tree is to start with the roots. Happy roots = a healthy tree!

    if you choose to use a heavy mix like MG as well as trying to amend it that is your choice. I also understand if life is very busy for you and growing is just a fun place for you to relax and grow quickly.. I certainly understand about grabbing a quick bag and thinking it will work.. But, for how long?

    i am here to just give my opinion to the new growers who would like to learn and understand that if you give a little extra time in the beginning for the overall health of your trees, they will give back to you what you put into the initial understanding and time needed to achieve the easiest way to make a proper mix for your trees. It does take time ( in the beginning to understand). I will admit that.... But it is worth it in the long run. When I make my mix it doesn't take me any longer to whip up a batch then it would be to pull a bag of that heavy miracle grow around to my back yard. I personally do not buy it.. If I do use a bagged mix to make a batch of 5-1-1. It would be for the peat needed and I would grab a bag of Fox Farm ( Ocean Forest). Or I would look for the Farfard product.

    i don't have any issues with my mixes during the winter with Nats etc.. I do have to bring in over 200 trees during the winter for their dormant period. ( Plumeria and other tropicals) Even my trees under T-5 lights for the winter are nat free.

    People talk about watering with a well draining mix. I would be the first to admit that I was worried since my job takes me out of town for days at a time, sometimes for 4 days. Watering isnt a problem even with the triple digit Temps we are having in Virgnia . ( I do have to keep a close eye at these extreme temps tho) I have adjusted to their needs and my own time frame for keeping them watered properly. I will water in the early morning or evening, which ever meets my needs. It's all about what you want and how much you are interested in what you enjoy. I don't have to water every day. I will and do pay attention to certain trees that might need it more so than others, but that comes with understanding your trees.

    I just wanted to say thank you to Al and tell you all that I have learned so much from you and others here on these forums. Growing is a hobby for me and a place to go and that takes me away from the crazy daily adventures that I deal with. Coming home to see my trees blooming and being so healthy is a great feeling and that comes from putting in a little effort at the beginning to see the rewards . Now, it all so easy...

    Thanks for this information, Al. I'll never look back...

    I hope this has helped a few ...

    Take care and enjoy your growing experiences!!!

    Laura

  • jane__ny
    8 years ago

    Irene, I've had that happen even with small bark. Those gnats like moisture. Either you are overwatering or the soil was infested when you used it.


    If you see gnats, or the bagged soil is damp, do as Sam suggested. Dry it out. Kills the gnats and eggs.


    I drag the bag outside and slice it open on top exposing the soil to the sun. Leave it there for a week until it is dry as a bone.


    Now my other suggestion is to watch your watering. You may have skylights, but they do not substitute direct sunlight. Light intensity diminishes by every foot from the plant. Let your plants dry out. Those gnats do not live in dry soil.


    Jane

  • jane__ny
    8 years ago

    Thanks for your response, Al.

    You are absolutely correct in everything you say. However, I find if things get too complicated or scientific people run for the hills. I tend to be a bit obsessive about my orchids. I spend endless hours trying to research their natural environments and try to mimic those conditions.


    Its my hobby and I love doing it. But if I push my knowledge on new growers, their eyes glaze over. I have learned the best way to teach people about growing is to make it simple.


    Simple enough to keep the plant growing and keeping the maintenance simple. I work hard teaching orchids in a way to make the grower successful. Maybe not 'perfect' but their plant stays alive and blooms.


    Growing is addictive if successful. Yes, growing in the perfect potting mix can help them be successful. But not always...light and watering are a big factor too.


    So, I tend to start teaching in a basic way. I know how they can keep a plant alive and bloom. Usually it requires repotting and increasing light. I have found this can turn a plant around more than any single thing. I always favor light as it tends to be the most deficient factor with people growing houseplants. The soil might be poor, but increase the light and you get growth.


    I have never seen anything work better than light. I am not a scientist, nor spend endless time researching what I observe. But I am convinced that lack of light is the cause of most houseplant failures.


    My opinion, observation. Nothing scientific, just experience.


    Any mix that allows good drainage is fine with me. As far as perched water, I've never run into that problem but maybe because I tend to underwater and usually have my pots raised on a wheeling tray with a saucer. I'm not sure, just not something that ever created a problem for me. I always advise people to let the pot drain and do not water again until they stick their finger down in the mix to see how damp/dry it is. I'm very strict about that.


    Overwatering and poor light is the biggest contributor to poor growth IMO.

    I also feel that if the plant is growing and looks happy, I'm happy. Maybe the roots aren't that happy, but if the plant looks good and smiles at me, that's all I ask for! What I see outside the pot, tells me what is going on inside the pot. Plants have a way of letting you know :-))


    Jane

  • Rosie1949
    8 years ago

    Well said, Jane!

  • jane__ny
    8 years ago

    I agree again with you. Proper information should be made available but not to a point where someone feels they have no choice and give up the joy of growing. I like to give people the choice with their orchids or houseplants. Many people I meet are fairly new at growing. Some only grow to decorate their house or patio. They want flowers or a nice green plant in their living room. They show little energy toward learning more, they want easy.


    I would say 80% of people buy their first orchid without researching or learning anything about the plant they grow. Then there are those who toss the plant and just buy another one. Just visit the Orchid Forum where you will see so many people who ask for help after the plant is almost dead. If the folks on that forum got too technical we'd get a thank you or never hear back from them. I like to keep people visiting and coming back for more information when they have the interest. It seems gradual as they have more success. I like baby steps.


    I have clients who only want flowers. They do not want to get involved in providing the proper environment, or learning what the plant requires.


    I take their plants after they bloom and bring them to my house to grow them and return them when the plants are in bud. This is not unusual. I had a similar experience in NY. Many offices, doctors, dentists want pretty plants for the waiting rooms. They do now want to get involved in keeping them that way. In Florida, you meet many people who want beautiful plants for their patios and homes. Surprisingly, it is usually younger people who have little time or patience, with older folks they tend to stick with the methods they have used in the past and are difficult to change. I could tell so many stories!


    My experience is to help them find a simple way to correct what is wrong and give them some success. Many times, it sparks an interest to learn more. That is my goal. Sometimes it doesn't and that's okay too.


    As far as my Pachira, I was thrilled to see the roots. This was a neglected plant which was terribly root bound. My kitty used it as a litter box! The base roots had grown into the patio which is laid in sand. It was very difficult to move the pot and tear those roots. I had to get help. The root ball was very compressed. I was expecting the worse. The roots were brittle, no rotted roots I could find. I decided to not do a major root prune but did remove at least 1/3. This tree was way overdue for repot. Should have been done 3 years ago. I just didn't get to it.


    I'm content with the situation. The tree does what I want it to do. Provide shade to a very hot patio. I have some small orchids growing on it and have strings of tiny solar lights which look pretty at night. I'm happy with it and that is all that matters to me.


    I appreciate your opinion. Wish I had heard from you when I first posted about repotting. I had a few questions, but its done now and the tree appears find and has not skipped a beat. I'll wait a month before celebrating.


    Thanks for your feedback,

    Jane



  • Rosie1949
    8 years ago

    Jane I agree with your opinion. And I appreciate the other opinions.

    As long as things are relatively simple and the results are satisfactory people will grow plants. Make it too difficult and you lose them. That also pertains to many hobbies AND subjects! Not everyone can follow growing to the letter whether it is because of finances, or just plain unavailability. I would rather do what I am doing and have the surprisingly good results I get than to NOT grow at all because I cannot do it "perfectly" with only what some people perceive is the correct way to grow.

    As long as I am happy and my plants are happy that is all that matters. I love to read a lot of the threads and gather all of the opinions and information I can. All of it is needed to help a person achieve their goal considering the supplies and money you have to available to you to work with.

    There are so many correct ways to do things and achieve great (or even just good) results! I hope everyone finds their own "way" that makes them and their plants happy! Rosie

  • jane__ny
    8 years ago

    You said it all, Rosie!


    Jane

  • Rosie1949
    8 years ago

    Thanks Jane. BTW, I have followed you! Rosie

  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago

    Just as you can't expect people with no interest in learning to learn anything, you can't expect growers who wish to use knowledge as their primary tool for improving the growing experience to be happy with information outlining the same methods that bring thousands of growers to the forums looking for resolution. There is no question that anyone/everyone can benefit from an increased understanding of how to coax plants into maximizing their potential, but not everyone can benefit from methods that leave so much potential lying on the table. The grower who wants to rid his plants of as many limitations as possible is left helpless without the information that allows him to do so. The grower who has no interested in the finer points of growing well can easily ignore offerings he feels are too technical, but those who wish to excel need technical information and need experienced growers who can call attention to suggested practices that have inherent limitations. Middle of the road proficiency is fine for those few who are happy with just average, but if there has to be an assumption, let's assume everyone wants to excel rather than everyone will be happy with 'middling'.

    The volume and type of mail and messages I get, and the response to the still very active thread with nearly 3,500 posts I started back in 2005 (see it here) as well as general response to info I provide tells an entirely different story about what kind of information people embrace. A close look shows that the only real resistance (eyes glazing over) to dissemination of information that leans toward the technical or scientific comes not from the authors of a thread, but from other thread participants whose offerings might be called into question because of their potential to levy limitations on the growing experience of others.

    “The destroyer of weeds, thistles, and thorns is a benefactor whether he soweth grain or not.”

    --- Robert G. Ingersol from Some Mistakes of Moses

    Take care ~ Al

  • drew51 SE MI Z5b/6a
    8 years ago
    last modified: 8 years ago

    I make 3,500 posts a year, so as a response for a 10 year period I would describe as dismal at best. Most seek information at the university extension offices and private nurseries.

  • John
    8 years ago
    last modified: 8 years ago

    "Most seek information at the university extension offices and private nurseries."

    Perhaps before the advent of Google. In 2015, the internet and Google is in our pockets and, in many cases, Googled questions about gardening lead here.

    That your posting habits and advice is so prolific would seem to confirm this.

  • gardengal48 (PNW Z8/9)
    8 years ago

    Every now and again a particular post will strike my funny bone and make me chuckle......the following is just such a post: "I make 3,500 posts a year, so as a response for a 10 year period I would
    describe as dismal at best. Most seek information at the university
    extension offices and private nurseries."

    The correlation between the frequency of posts by a specific member (completing disregarding the value of their content) and the number of responses to a single post (or a series of identical threads due to previous posting limits) just doesn't exist! There is no other thread or topic on any of the GW forums (or any other gardening forum/chat room) that has garnered anywhere close to the activity and responses that Al's container soils and water movement thread has. Obviously, there is considerable interest in the topic and the number of posts on this forum (and others) related to that topic provide additional evidence, the vast majority of them positive in nature.

    It is also not at all common to have a thread like that come up as its own Google search topic and with references made to it on several dozen other websites.

    And with access to the Internet available via any smart phone, notepad or other mobile device, not to mention home computers and laptops, you can bet your bippy that most are NOT seeking info from extension services or private nurseries but from Internet searches, if nothing more than for convenience's sake......not to mention that a fair percentage of the population has no idea what a university extension office is or the type of information they provide. And unfortunately, good "private nurseries" are becoming a dying breed and with no guarantee of being a source of accurate horticultural information in the first place.

    The chuckle-inducing post just has an air of illogic and unreality to it, not to mention a distinct whiff of sour grapes.

  • jane__ny
    8 years ago

    We've been down this road so many times, its getting so tiring. Who cares who posts the most. Seems so immature.


    The responses and feedback from all those doing searches is what counts. No way to quantify how well received anyone's expertise is except to keep track of those who search and return. I suspect there is a large discrepancy between the two.


    Seems to me on some forums, people ask for help and disappear. Does that mean they followed the advice given or that they moved on to other searches?

    There should be room for everyone to give opinions and advice in a friendly, helpful way without it becoming a competition or argument. People can decide what help to follow according to their needs or limitations. I'm finished with this thread...

    Jane



  • Rosie1949
    8 years ago

    Jane your comments make so much sense.

    Gardengal I had to laugh when I read that also. It is called EGO.

    Jane, like you, I am also finished with this thread. Rosie

  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago

    I'm not sure it was a boast, but I'm not sure what he said or meant, either.

    Al

  • Irene
    8 years ago
    last modified: 8 years ago

    Okay, kids, professionals, enthusiasts, hobbiests and Non-GMO lobbiests (trying to be all inclusive here). I am very grateful that experienced individuals are actively surveying these boards and offering their insite, be it a brief Coarse on soil make-up and the particulars of particle size (very enlightening & helpful, thank you, Al!). And the reminder to mind the basics: light, light, light & moisture monitoring. I honestly expected my post to hang unanswered for an eternity.

    I will admit I was in a rush to sow some seeds in the hopes of harvesting some homegrown organic produce and while i took detailed notes on each plants preferences and preferred soilmates when laying them out, I cut corners on soil preparation, I had been advised to avoid the MG Organic potting soil by my mom who recently had her own bought of the Gnatsies; as she's not growing edibles or particularly anti-farmiceuticals she used a chemical to treat her indoor invasion. I gathered a few recommendations for local nurseries but in the end, anxious to get growing, I grabbed the readily available sack of Organic soil at a Big Box. Because I want to direct sow/ disturb the plants as little as possible, and was afraid the fine seed starting medium would get waterlogged and not have much nutrients in it I opted for potting soil. It just so happened mold gnats sprung forth the minute I opened it. Having dealt with these guys before I thought nothing of it, get the soil covered, let it dry... I do not have an outdoors option for pre (re) sterilizing soil. I expected something bought indoors in the indoor plant section would be ready for indoor use. I am working with a lot of natural light, but fear the spectrum may be limited by a softening filter (see photo) so I am supplimenting with 26W 6400k grow lights. Though my Plumeria which has been nothing but a barren stick for the past 2yrs is thriving with no additional light, it has 2 new branches since i moved in in mid April and a third node in the works. - its leaves are much larger then those on its parent plant who gets to enjoy a sunny porch. My aloe which bloomed (in upstate NY!) is in need of repotting (as always), it started as a $4 babe, in its youth it was potted in the ever handy MG cacti soil but with added clay beads and in my days of weaker conscience fed MG crystals- ceased due to the over leggy growth of my Jade. I will admit my cheap baby succulents reached jurassic size remarkably quickly... But now days everyone gets bat guano and MG Organic Choice liquid plant food (I do want to break from the cycle of Big Box consumerism). I am very happy doing research online as both novice and technical guidance is only a quick browser search away. I just purchased a beautiful Meyer Lemon loaded with small fruits at a very upscale nursery. I was blown away by the selection and scale in their botanical gardenesque greenhouses.The staff was also friendly and eager to help but most had to radio someone else who knew only some of the answers, also the fertilizer selection in stores pales in comparison to online assortments. I work full time and would not be sending soil samples of my dozen-some pots to cornell cooperative extension, so I want to get the appropriate equipment and knowledge to do something myself, at home, hence Google911. I should probably opt for visiting hydroponics shops for immediate answers/products related to my type of growing if I am going to get the best results

    very sad seedlings
    Meyer meets Skylight 8pm

  • Irene
    8 years ago


    Well plummed Plumeria

  • Irene
    8 years ago
    last modified: 8 years ago

    I rearranged the plant scape, elevated the surviving seedlings so they are closer to the grow light and deepened the gnatnix, gnats are STILL overwhelming in number, planning to dump some obliterated pots.. still torn between attempting soil sterilization with heat gun (the frugal side of me who really likes playing mcguiver and hates following recipes) or total replacement (Al's gritty mix perhaps? I like the idea of being able to water frequently without fear of drowning, seems more flexible- if you over feed you could rinse it out faster, etc..) I am hosting a housewarming mid august and need these gnats eradicated. good news is I am seeing true leaves and new height after some of these seedlings stood dormant for a week! hooah!

  • tapla (mid-Michigan, USDA z5b-6a)
    8 years ago

    Irene, I'd like to send you a personal message, but your settings don't allow. Maybe you'd consider sending me your email addy in a Houzz message?

    Sometimes explanations get lost in the back and forth between people with different viewpoints, but the fact is, soils with a large % of fine particles are always going to pose limitations that result from too much water retention. Even though that fact is carved in stone and can't be argued (because it's governed by predictable laws of physics), there are those very few that insist on arguing the point over and over. Any roots existing within the perched water column will be deprived of O2 for the duration of the saturation. I made that last period bold, but you probably didn't even notice. ;-) The question isn't whether geography or hot dry hurricane windy conditions lift the limitation imposed by the saturation, they don't; the only question is, "How long will the limitations last". In many cases, the answer is measured in weeks, in some cases, in days. A good guess about how a soil like Mg amended with some bark & perlite (let's say 5 parts soil, 1 part perlite, and 1 part pine bark) performs might go like this:

    Day 1, grower waters established houseplants heavily, to beyond saturation, so water exits the drain. At that point, limitations are most severe.

    Day 2-5, the degree of limitation gradually decreases until day 5 when the soil is reasonably well aerated and the plant is pouring energy into replacing the fine roots killed by the soggy conditions.

    Day 5-6, The plant has grown at it's best these 2 days because the soil is moist and about as well aerated as it can be. Almost all the roots killed by saturation have been replaced at a considerable cost in terms of energy outlay. The plant is pretty happy, but the soil is now becoming too dry for the plant to efficiently take up water and the nutrients dissolved in water. It's on the verge of suffering drought stress.

    Day 7, the grower waters, cycle begins anew.

    That isn't an exaggeration. It describes a soil that needs weekly watering.

    Now, a soil in a soil that holds little perched water. The soil is based on a very high % of coarse material (pine bark, perlite, peat or a water retentive bagged soil). NOTE that the ingredients are the very same ingredients as the soil discussed immediately above. The ONLY difference is the ratio of ingredients used.

    Day 1, grower waters established houseplants heavily, to beyond saturation, so water exits the drain. At that point, limitations are most severe, but still minimal because the soil is designed so the ht of the perched water column and saturation is minimal.

    Day 2, Perched water is gone, the plant is enjoying a well-aerated soil from top to bottom. Fungus gnats on notice to find more favorable accommodations. This continues until day 4 or 5.

    Day 4 or 5, fungus gnats have sent out scouts. Other's making preparations to leave this God forsaken place. Plant still happy, but need to water growing imminent.

    Day 5, grower waters & cycle begins anew.

    The only price paid for the second scenario is the need to water more often. The first soil was 'amended' with pine bark and perlite, so those would have been on hand anyway. Some might say I'm not going to water 100 plants every 4th, third, every other, or even every day. That's fine, but that convenience demands a soil with enough water retention to get you through whatever interval is desired by the grower. The grower might like the respite from frequent watering, but the plant won't. Convenience very often comes at a price to the plant. That's not judgmental, it's simply how things work.

    The gritty mix you mentioned holds no perched water if made correctly, so plants are happy from watering time until such time they need another watering. Again, because we've moved away from a perched water table entirely, the need to water the gritty mix comes more frequently than say the 5:1:1 mix, and much more frequently than a soil like you're using. It's also sometimes a challenge to find the exact ingredients, but because the gritty mix recipe I offer as a starting point is nothing more than 1 way to embody a concept, it can be worked around fairly easily.

    I'll watch for a message with your address.

    Al