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Watering issues

Posted by lenle 4 (My Page) on
Wed, Mar 20, 13 at 18:51

At the risk of being lambasted, I need advice/help with solving a watering issue. In the past, I've certainly had trouble with underwatering. The obvious solution is to water more... I've tried finding a good balance but have yet to achieve it.

I'm using either gritty mix in terra cotta pots for my succulents (jades, snake plants and ponytail palms) or a mainly bark mix in terra cotta pots for my holiday cacti. I'm zone 4 - NY State - where winters are absolutely brutal. It gets dry inside in winter, but I have humidity trays near the plants that need humidity. The jades I'm currently watering every week and a half (stepped up from monthly watering). I have several with very soft, flexible leaves (and dropped segments) and crystallized leaves. My ponytails are easier to manage and are relatively healthy. The holiday cacti get watered every five days, roughly, again depending on how thirsty they look. Lighting could be better, but for now they're in an east window with daylight bulbs (1,650 lumens total). I have a drilled well which means I have hard water. I also fertilize at every watering - a diluted dose of Foliage Pro.

I've lost a few that seem to have fallen apart right where they go into the soil, others that shed dried leaves until nothing remains and have yet more that have leaves that are perpetually flimsy and flexible (succs and holiday cacti alike).

Am I looking at a combination of not enough light with too much watering or is it something more related to the dormant season?

Any and all advice is appreciated. I've been trying to get these plants to plump back up going on almost three-four months now.

TIA- Jeni


Follow-Up Postings:

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RE: Watering issues

Holiday cacti and jades should be showing some signs of growth this time of the year.
Our zones are different but winter equals plenty of snow here too some of our plants may be common
By the way you described your jades and holiday cacti and the effects you have from watering them our soil mixes are more than one substrate apart.
If to help we know they wont be pretty ........got pics ?

Demo of an EC growing but needs some water soon


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RE: Watering issues

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Wed, Mar 20, 13 at 20:17

Are you flushing the soil well each time you water? That becomes more critical because of your suspected well water issues and the fact that you are fertigating at each watering.

Do you have a lot of plants? have a friend nearby with a well and a R/O water treatment set-up who you could borrow water from?

Al


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RE: Watering issues

Near as I can tell, I am flushing the mix well. I usually keep a tray under the pot and pour a good bit of water all around the plant, let it drain and then pour the water in the bowl back into the mix. I do this several times to ensure a through soaking.

I have a small number of plants in regular potting soil, mostly because I haven't had the opportunity to repot them. They're also in front of a southern window. They do not have the same issues I'm having with the ones I spoke of above. I unfortunately do not have access to a RO system... The most I can manage is collecting rainwater in the spring/summer and if need be, water from the nearby river.

I can get pics tomorrow once I've reclaimed my camera.

Thanks again!

Jeni


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RE: Watering issues

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Thu, Mar 21, 13 at 21:23

Do I understand correctly, that you're pouring the effluent that collects in the saucer back through the soil to ensure the entire soil mass gets moistened? If that is so, then all the salts that would normally be flushed FROM the soil to collect in the saucer and get discarded are getting recycled right back into the soil, so the soil solution would become continually more concentrated with dissolved solids.

Al


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RE: Watering issues

If I follow you, Al, you are correct. I have a gallon jug that I typically empty into a pot... I thoroughly drench it on the first go, but in the second and third drenchings, I put the pot into a bowl and reuse that water until the pot is heavy.

If that is what's causing this (even in gritty mix), then I really feel like a fool. I thought what I was doing was harmless.

Jeni


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RE: Watering issues

Got roots ?


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RE: Watering issues

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Fri, Mar 22, 13 at 9:53

One of the most significant benefits of using soils that allow you to water copiously with no concern about potential root problems related to excessive sogginess is the fact that the ability to flush the soil at each watering prevents dissolved solids (salts) from building up in the soil. Ideally, when you water you would allow the effluent passing out of the drain hole to run down a drain or collect in a saucer. When it DOES collect in the saucer, the container should be lifted above the effluent, so after it exits the pot, there is no way the dissolved solids contained in the effluent have any chance of getting back into the soil. I set my pots up on little 1-1/4" blocks that rest in the saucer. I don't need to empty the collection saucer because the water that collects there can't get back into the pot. It evaporates and contributes to the area humidity, but you could empty the collection saucer if you like, or water over the sink.

The higher the level of dissolved solids in the soil solution, the more difficult it is for the plant to take up water. So a soggy soil that impairs water uptake combined with a high level of salts in the soil solution is a double whammy for a large fraction of growers who use heavy soils that don't allow them to water so they're flushing the soil. This problem is always most prevalent in the spring, after a long winter of watering in sips, or in your case, of pouring residual salts back through the soil, which ensures a gradual but continual increase in the level of dissolved solids that affect water uptake AND nutrient uptake.

If you're using a fertilizer that might not be a problem if you're watering properly, it can quickly become a serious problem if you're NOT watering properly. We know the impact of dissolved solids on the uptake of water also limits the ability to take up nutrients, but when dissolved solids accumulate the ratio of nutrients to each other in the soil can quickly become skewed, which has the effect of one nutrient present in excess making it difficult or impossible for the plant to take up another nutrient. This is very common when using fertilizers with too much phosphorous, and is quickly exacerbated when the soil isn't flushed regularly.

Al


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RE: Watering issues

Thanks for the insight, Al. I've tried the wait and see approach with a great deal of trial and error to see if I could pinpoint what I was doing wrong. After a bit, I began to worry that I would run out of plants long before I ran out of ideas as to what could be causing this problem!

I've been using Foliage Pro (the ratio that was recommended for use w/ Gritty Mix) on all of my plants, regardless of what they're potted in. I give a 1/2 tsp per gallon at each watering. My holiday cacti also have Osmocote in their mix.

I now know I've been watering improperly and will no longer re-use my run off. Would a thorough flushing of the mix w/ plain tap water be alright this weekend? Or would it be better to water as normal (with 1/2 tsp of FP) but not recycle the run off back into the pot?

I'd like to be able to do the 'water weakly weekly' routine if at all possible, unless there is no real added avantage to that.

I'm also curious at the rate of a 1/2 tsp of FP to each gallon of water, is there a lot of waste of the FP? Initially that was my concern and why I started recycling the run-off.

Jeni


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RE: Watering issues

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Fri, Mar 22, 13 at 15:57

If you're using the gritty mix, there is very little possibility that you're over-watering, or that flushing the soil thoroughly would create a problem, so I would do that. If you didn't screen the mix carefully, and there are fines in the soil, then use a wick and tilt the pot after you flush - then water normally. I use a level 1/4 tsp/gal of FP 9-3-6 every time I water, and I've been well pleased with the results ever since I settled on that amount, so I'm thinking you could cut back on the amount of fertilizer you're providing. I'm pretty sure that with the 1/2 tsp/gal + the recycling of the effluent, that your plants are seeing some fertilizer burn.

There are some advantages to fertilizing every time you water, and at 1/4 tsp/gal, you get about 800 gallons of fertilizer from a quart of fertilizer. @ $25/qt for the fertilizer, a gallon of solution costs about 3 cents per gallon. Most people would hardly think twice about buying and paying for the electricity augment light levels for their plants - and that's a much more significant outlay than the small amount of fertilizer that might get discarded after passing through the soil. If you want to, collect the effluent in a bucket & spread it on the lawn or your garden/beds.

Plants that are fertilized at higher rates (luxury levels) often show symptoms of deficiencies when the concentration of nutrients in the soil returns to the adequacy range, so that's one + of fertigating @ each watering (it won't happen). Another is, even in nature, nutrient uptake is very closely linked (almost directly) to water uptake, the primary modifier being temperature, which isn't a particularly significant factor when houseplants are the topic. I said that so I can say there is some benefit in not having to keep track of what needs fertilizing when. I fertilize and water everything at nearly the same intervals, and at the same fertilizer rates, and for the last 15 years or so, my plants have all been practically free of blemished foliage. You're trying to do essentially what I (and many others) have been doing, so I expect that once you get the bugs worked out & get your dosages refined, you'll begin to see how easy it can be. I'm pulling for you! ;-)

 photo Laughing.jpg

Al


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RE: Watering issues

I don't mean to sound so terribly frugal! I have to special order the FP since it's not available locally, which tends to get a little expensive.

I screened the fines as best I could - I plan to invest in something more accurate than the kitchen strainer I've been using, just to be on the safe side. Until then, I'll plan to use wicks.

Just to clarify too, when you say to flush you mean to dump a good amount of water through the mix (with our without fertilizer) and then going forward, water in a similar fashion?

As always, thank you for your insight and help Al!

Jeni


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RE: Watering issues

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Sun, Mar 24, 13 at 14:13

What you said about being frugal made me think. I think that in some aspects of my life I'm a frugal person, and in some aspects I might be a little closer to extravagant - so on average I think I'm sort of middle of the road. As I think about it, it's never the instances when I feel I'm being frugal that cause me any guilt, but I've suffered some of those pangs over being extravagant from time to time. There is no judgement for being frugal - I think were meant to be that way.

I only did the math so you could get some perspective on the pennies that fertilizing often and flushing the soil costs. Using one of the granular solubles in a 3:1:2 ratio like 24-8-16 would even reduce the cost further, but there is a pretty significant difference between what those fertilize offers and what's offered by the 9-3-9 by Dyna-Gro. If you want to use something like 24-8-16 or 12-4-8, I can help you get the most out of it.

Flushing the soil can be done with or without using fertilizer in the solution. If you fertilize at every watering, it serves like clicking the "Return to Defaults" button on your computer. Even if you're using a fertilizer, the ratio of which isn't a good choice, it resets what nutrients are in your soil so harm is less likely.

For instance, If you are using 5-15-5, you're using about 9X as much P as your plant can or will use. If you're NOT flushing the soil, that 9X more P than you need quickly multiplies each time you fertilize (because it stays in the soil), so soon there is so much P in the soil your plants can't take up K, Ca, Mg, Fe (especially), Z, Cu. Plus, the extra P causes pH to increase, and the higher level of dissolved solids in the soil solution prevents your plants from properly absorbing water.

When I water, I water slowly, covering the whole surface of the soil, and I stop when water starts to exit the drain. This means that 10-20% of the water I applied will pass through the soil. That's not the best way to water, though. Best would be to apply enough water so the soil mass is saturated - wait 10 minutes or so, then water again so 15-20% of the total volume of water applied in both applications drains from the pot. The water should drain away so there is no chance it can be reabsorbed into the soil, so there must be a break in continuity between the soil solution and the effluent that collects in the saucer - otherwise the salts you flushed from the container will quickly reach an isotonic state (equilibrium) in the amount of salts in the solutions, and most of your efforts at flushing the soil will have been for naught.

Al


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