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Smart pot mix, lets have some fun

Posted by stimey 6a (My Page) on
Tue, Feb 18, 14 at 16:56

I posted this over in the tomato forum but was encouraged to post it over here.
I know its early and not even close to time to be setting out toms yet, my question or request is what you guys would think a good mix would be for toms in a grow bag/smart pot? My thought is a modified 511 these grow bags will be on the ground so virtually a raised bed, these smart pots are home made so they are 28" OD x 28" tall they are a heavy polyester. I am thinking of something like 5-2 Pine bark fines and DE, I am thinking I need a bit more water retention due to the hydraulic affect the ground will have on them. I am thinking of avoiding peat, not certain why right at this moment, I know DE retains moisture more the turface, I am not certain if it retains more then perlite though. I also considered 5 pine bark 1 DE and 1 perlite, I am not apposed to peat, and have multiple ingredients to work with so give me your thoughts, I have more than one smart pot so why not try two different mixes? My pine bark at the moment is whatever would go through a 3/8 screen, it is really nice looking bark with some nice fines in it. So I am looking forward to hearing your ideas. Thanks


Follow-Up Postings:

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RE: Smart pot mix, lets have some fun

"I am thinking of something like 5-2 Pine bark fines and DE...I also considered 5 pine bark 1 DE and 1 perlite..."

Both sound like reasonable mixes. DE holds more water than perlite, so the former would boost water retention. You can certainly skip peat if you want, especially if you're using DE, your bark has lots of fines, and you're growing in such large pots (75 gallons or so?). I'm boosting the percentage of fine material (plus adding DE) in my fabric pots this year because they dry out so quickly, but I grow in mostly 7-20 gallon sizes. Speaking of pot size, are you planning on growing multiple plants per pot? I ask because 75 gallons seems like overkill for a single plant -- in my experience, 10 gallons will suffice (if you don't mind watering daily) and 20 gallons is ideal.


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RE: Smart pot mix, lets have some fun

shazaam LOL you are correct I have not even figured volume until now, my neighbor is a seamstress that is going to sew these filter bags up for me, at the moment these are 28" OD x 144" long, I guess I should spit these down the side and reduce diameter and height. She has not started on them yet, I have 4" ones that I have sewed the bottoms up on they are 5" tall I am using them for my seedlings just to see how they work. Is there any other ingredient that would be beneficial? I am just not used to growing in such a simple mix, I mean if it isn't some kind of 14 secret elements how can it possibly grow anything? Just kidding, this is fun hearing what you guys suggest.


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RE: Smart pot mix, lets have some fun

Be sure to add Dolomitic Lime to your bark-based mix. I'd add a light dose of slow-release fertilizer, too.

Josh


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RE: Smart pot mix, lets have some fun

Thanks greenman28 I agree I will do both,
This is the kind of discussion that I wanted to hear when I made the original post, this is how I learn from you guys and come up with new ideas. I have failed more then succeeded but I really had fun doing both and learned by failing and succeeding. With me it is about learning, and having fun doing it, sometimes you can stumble on something that works. Its not that I cant afford pro mix or what ever it may be, I just like making my own, I have some lignite that I have put in one of my raised beds, I also have some oxidized lignite that is a very high content of Humic acid, now that is a completely different subject in its own or is it? I have some of this that is pelletized and claiming 70% Humic acid, will it work don't know gonna find out this year, probably wont use any of it in containers though.


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RE: Smart pot mix, lets have some fun

Also, be sure to pre-moisten your bark before mixing so that there aren't any dry spots in your containers (or areas that resist wetting). Plus, the Lime needs moisture to spread evenly throughout the mix and activate.

Josh


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RE: Smart pot mix, lets have some fun

Gotcha greenman28 will do, I dont see any value in adding any nutrients in my mix other than the slow release, I use foilage pro for a lot of my indoor stuff or containers that wont be affected by the ground (Hydrology), but what do you think about the addition of Humic acid? or anything else as far as that matters?


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RE: Smart pot mix, lets have some fun

greenman28 are you saying I should wet my bark before mixing? or adding moisture after mix is mixed? Keep in mind I am talking about smart pot on the ground not a container, I know you probably know that already, but I almost forgot.


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RE: Smart pot mix, lets have some fun

I'm not sure about the humic acid or other additives.

As for the bark - wet the bark before mixing, perhaps in a container the night before. And add more water while mixing, a little at a time, until all of the ingredients are thoroughly moist. Warm water works well.

Josh


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RE: Smart pot mix, lets have some fun

I will be making mix this week end, I have made it several times but have not used water as I made it I have always just whetted it very thoroughly after placing it in the container and waited a day before planing. I will fallow what greenman has suggested. Below is a list of what Humic acid is to soil, granted this is a statement made by a company that sales it in varying forms making it by a process of oxidizing lignite (Brown coal) I know that containers are not good vessels for microorganisms to come into play, or that is the way I think I understand what I have read. This thread has really been educational and fun, thanks guys.
Increases soil carbon
Improves plant health
Improves germination and viability of seeds
Chelates macro and micro nutrients to increase availability to the plant for a longer period
of time
Increases cation exchange capacity (CEC)
Improves soil structure for better aeration and water movement
Stimulates beneficial microorganisms, which can improve long-term soil pH
Especially effective on sandy soils


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RE: Smart pot mix, lets have some fun

I know a lot of folks who use humic acid, et cetera, but my concern would be the effect on the pH of the bark mix, which is already quite low (before the Lime is added). Bark has compounds similar to humic acid, and once composted will contribute humic acid to the overall mix, if I remember rightly.

Josh


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RE: Smart pot mix, lets have some fun

Stimey: I've grown tomatoes in 25-gallon smart pots since 2008. I mostly grow big heirloom beefsteak types. For the past three, I used 5-1-1 mix. I didn't alter it the first year, but by year three, I altered it to be 5 parts PBF, 1 part DE (NAPA #8822) and 1 part well aged compost. I also used 1 tablespoon dolomitic lime and 1 tablespoon of controlled release fertilizer per gallon of mix. I only grow one plant per pot. In my conditions, I usually have to water every other day when the plants are full grown and the temps are high. This is how they looked about six weeks after planting out.


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RE: Smart pot mix, lets have some fun

Those are BEAUTIFUL!!! You are obviously doing something right!
If you don't mind my asking what is DE?


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RE: Smart pot mix, lets have some fun

DE is diatomaceous earth, made up of the fossilized remains of diatoms, which are a kind of hard shelled algae made mostly of silicon. The NAPA auto store sells a form of it that has been heated to a high temperature, called Floor-Dry, part #8822. I used it in place of perlite in these containers because it holds more water. Because smart pots breathe, they do need to be watered a little more than hard-sided containers. Adding DE to the mix makes it a little more water retentive. You can see a picture of it in the thread on using it to start seeds.


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RE: Smart pot mix, lets have some fun

I sure have learned a lot from this thread:)
Back to DE, I thought I read somewhere you had to be all careful handling it? Do you just mix it, how do you prevent yourself from breathing it?


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RE: Smart pot mix, lets have some fun

You should be careful not to breathe the dust from any component when mixing any soil mix, including peat, perlite, vermiculite, bark or DE. The calcined DE I'm talking about is actually less dusty than perlite or peat. (Calcined means it has been heated to a very high temperature, which makes it very hard. It won't dissolve in water or be easily crushed.) The dust from perlite is the worst in my opinion. You really should wear a mask when working with it. I usually just rinse the DE when I'm working with it.


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RE: Smart pot mix, lets have some fun

greenman28 good point about the ph, here at my house the ground is very alkaline, one of the reasons I use the humic acid pellets on it, I think I will leave that out of my mix.

Ohiofem I like what you have stated about the well aged compost in the mix, mainly because I have some LOL but I always read that we should avoid organics in containers? I don't understand why completely, it adds moisture retention as well as nutrient? what is the draw back on adding organics to containers? or am I reading wrong?


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RE: Smart pot mix, lets have some fun

As I said in the other discussion: I do substitute compost for some or all of the peat when using the mix in fabric Smart Pots that are on bare ground. The earth acts like a giant wick so the pot is more like a mini raised bed, and there is no perched water table. The roots actually grow through the bottom of the pot into the ground.

When making 5-1-1 for regular containers, I don't use compost or manure because the fine material can make the mix too water retentive. In any case, I don't count on the compost to meet the nutrient needs of the plants in a container. I use mostly chemical fertilizers in both situations. When growing in a regular raised bed or directly in the ground, I prefer organic fertilizers and amendments.


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RE: Smart pot mix, lets have some fun

My large pots have 5 holes on the bottom. each around 1" in diameter. I'm curious as to how much ground contact is needed to prevent perching.


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RE: Smart pot mix, lets have some fun

I think the whole bottom of the container needs to be permeable or gone for the container to act like a raised bed. I have some half whiskey barrels I drilled many one-inch holes in that I've used for melons and tomatoes. When they were in direct contact with the ground, they did not drain well whenever we had heavy rains. I set them on cement blocks so the holes drain over air, and found the drainage was much better. Keep in mind that the fabric containers "breathe" so moisture leaves the container through the sides as well as the bottom.


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