I don't always follow this advice, but it seemed wise when I read it:
If in doubt about over-watering, leave one or all plants unwatered UNTIL they actually wilt a little. If it takes days longer than you expected, you were overwatering.
I try to remind myself that too much water drowns roots, and both people and plants drown much faster than they die of thirst.
Container Soils - Water Movement and Retention III
Kev - it would be helpful if you got a wooden dowel or skewer, thin enough to sharpen in a pencil sharpener and long enough to reach deep into the pot. Insert the sharpened dowel and withdraw. Check it on your cheek or inside of your wrist to see if it feels cool, or note if it's visibly wet or dark/dirty. If there's evidence there is moisture deep in the pot, withhold water until the dowel comes out clean & dry.
Al
Took the words right outta my mouth!
Thank you all, just a little bit ahead of you guys, and girl, about checking a little deeper in the container. I've been using bamboo sticks for support and when I really looked at one and noticed how wet it looked. That's when I started digging deeper and found out moist the mix really was. Now I realize that I may have been a little hasty about my determination that the mix was too fast and wasn't holding water. Our 90+ temps have helped these pots dry out fairly quickly and I might be able to save a couple of the Beefsteaks.
Now that I'm aware of how water retentive this mix is I have cut my watering schedule way back, even though we're hitting 90 every day and when I check the soil a bit deeper you can tell how cool it is.
This message was edited May 4, 2012 11:02 PM
Watering technique is significantly under rated in its importance to container culture. I think the ultimate container gardeners are bonsai practitioners; this, because the work in shallow containers, which are much more difficult to grow in, they are growing in very small volumes of soil, and they are continually adding the stress of regular manipulation of their plants to the other adversities; so bonsai is container gardening raised to the Nth degree. I said that to give more impact to the thought that when a bonsai master takes on an apprentice, the apprentice time is usually dedicated to learning to water properly and in a timely manner before he is allowed to work on trees.
Of course, watering technique is closely linked to soil choice, and soils that hold too much perched water often don't allow you to water properly until the container is jammed full of roots so the plant uses the excess water the soil holds before it rots roots. Note though that just because there is no root rot is no good indicator that there is no inhibition of root function taking place. Any time the soil is soggy, root function is impaired and potential lost, no matter if there are rotted roots or not. Roots die quickly under airless conditions, so when the soil changes back and forth between soggy and containing enough air, roots die and regenerate with the cycle. The energy that goes into replacing the lost roots is the lost potential because the energy might have been put toward producing additional blooms, fruit, or in simply increasing biomass.
Al
It's funny that the symtpoms of too little water can also be caused by overwatering: it doesn't matter how much water is in the pot, if there are not enough healthy roots to take it up.
Too bad we don't think about the necessity of adding fresh air to the soil! Maybe if we had to bring home little bottles of "horticultural air" from the nursery, and pour them into the soil every few minutes, we would remember how important air is to roots.
High school environmental science needs to be re-evaluated, or at least taught to me again, it's only been 40 years... Of course, the only thing I can remember is that roots drink water, photosynthesis exchanges carbon dioxide for oxygen and Loraine C., my lab partner, was real cute with her Brooklyn accent...LOL...
LOL!
>> roots drink water,
And breath oxygen. In the dark, as I recall, even leaves absorb oxygen in order to keep metabolizing.
Rotts of real aquatic plants (I think) get their oxygen via sap, exported by leaves. I suppose they might get some oxygen from gas dissolved in water, but my guess would have been that mud (like in rice paddies) is hypoxic or anearobic.
I would have said that "roots don't have gills", but they do have root hairs which might be almolst as effective.
Ok, my highschool biology is rusty, but don't plant leaves "breathe" carbon dioxide and "exhale" oxygen?
OOOOOHH Man, what have I started now!!!!!LOL....
Plants don't actually drink water. They absorb it molecule by molecule from colloidal surfaces and from vapor in macropores. Plants use CO2 for photosnythesis, and O2 is a byproduct of their metabolism, but they need O2 in the root zone for normal root function and metabolism. If soils are soggy, they CAN adapt to some degree, but they don't handle the back & forth transition from saturated to well-aerated without rebelling.
The roots produced under hypoxic (soggy soil) conditions or under water are quite different from those produced in a quality container soil or other well-aerated medium (perlite - screened Turface - calcined DE - seed starting mix, e.g.). These 'water roots' are much more brittle than their counterparts growing in soil; this, due to a much higher percentage of aerenchyma (a tissue with a greater percentage of intercellular air spaces than normal parenchyma), and their construction is different as well.
Aerenchyma tissue is filled with airy compartments. It usually forms in already rooted plants as a result of highly selective cell death and dissolution in the root cortex in response to hypoxic conditions in the rhizosphere (root zone). There are 2 types of aerenchymous tissue. One type is formed by cell differentiation and subsequent collapse, and the other type is formed by cell separation without collapse ( as in water-rooted plants). In both cases, the long continuous air spaces allow diffusion of oxygen (and probably ethylene) from shoots to roots that would normally be unavailable to plants with roots growing in hypoxic media. In fresh cuttings placed in water, aerenchymous tissue forms due to the same hypoxic conditions w/o cell death & dissolution.
Note too, that under hypoxic (airless - low O2 levels) conditions, ethylene is necessary for aerenchyma to form. This parallels the fact that low oxygen concentrations, as found in water rooting, generally stimulate plants to produce ethylene. For a long while it was believed that high levels of ethylene stimulate adventitious root formation, but lots of recent research proves the reverse to be true. Under hypoxic conditions, like submergence in water, ethylene actually slows down adventitious root formation and elongation.
In essence, the structural variation of roots that forms in aqua culture allows the roots of the plant to get oxygen needed for root metabolism from plant parts above the ground instead of from the soil, as they normally would. The reason saturated soils in conventional container culture are so limiting is because roots cannot make the transition from a media that is hypoxic part of the time and well-aerated the rest of the time. The roots, when deprived of oxygen, simply die or are significantly impaired in function until aeration returns to the soil, a condition that is often seriously limiting and can even kill the plant outright.
Al
>> don't plant leaves "breathe" carbon dioxide and "exhale" oxygen?
Yes, when the leaves get enough light to convert the CO2 to O2. That take a lot of energy and reducing power.
In the dark, the plants can't produce oxygen. No photosynthesis. And yet a plant still has energy needs, so at night it "respires" - taking up oxygen and burning stored sugar - to keep it going through the night.
Even in heavy shade, more O2 is produced during the day than is consumed at night.
Roots never photosynthesize (even grown in wtaer and sunlight, they have no chloroplasts). Therefore they need oxygen all the time.
I never knew they could make their own internal aerenchymal snorkles to suck air down from above, but I learn something almost every day here on DG. Thanks, Al!
anybody know how to make this a sticky like the first two parts? don't want it to get lost...
Use the "Contact Us" feature at the bottom of this page and ask for it to be made a sticky.
Just sent the message; hope it works!
I'll probably be reposting another thread soon, as the longer threads take so long for those w/o fast net connections. Watch for that as a sticky candidate, too. Thanks!
Al
Al,
Thank you for the information and the link you sent. I'm pretty sure I understand the concept of the "'Gritty Soil", although there is alot to absorb and I'm sure there are some things I missed or didn't quite understand. The actual concept just makes sense... I will be heading out this week to buy the necessary parts. - I can already "see" my plants that I consider healthy now, becoming what is probably more healthy and starting better lives.
My confusion lies in the fertilzer. I just reread and got a grasp on the ratios, so that is no longer a question. The liquid I have/use for my house plants is MG 8-7-6 and that is clearly not a 3:1:2 ratio. I guess I will pick up a new one with a proper ratio while I'm out.
Do you fertilize every time you water since the soil is not already enhanced with such fertilizer as you would find in say... "MG Bagged Mud"?
I have some good looking Peace Lilies, Split Leaf Philos, Christmas Cactus, Budda's Hand, Scheffelera, Austrailian Tree Fern and some other random house plants that I feel will benefit greatly by this change. - Also I have posted a picture of another PL that my MIL asked me to place in ICU for her, as she nearly killed it (you may have read the thread in the Beginner Houseplants forum).The poor thing looked awful, and though it is still not (in my opinion) up to par, it does look much better than when I brought it to my house weeks ago. -- I am thinking of it being one of the first to be transplanted in the "gritty soil". Should I bare root it or since it is a bit of distress, should I just remove a good portion of the current soil and place it in the new soil, and try to remove the rest at the next repotting interval?
This message was edited Jun 10, 2012 1:01 AM
This message was edited Jun 10, 2012 1:05 AM
Though I have a number of succulents, most of my plants are bonsai or potential bonsai. I over-winter about 100-125 plants under lights. Those, I fertilize (during the winter) each time I water with a very low dose of FP 9-3-6 - 1/4 tsp per gallon of water. What allows me to do this is the free-draining soil. All of my plants are situated above a plastic dinner or salad plate that serves as a collection saucer, and I flush the soil each time I water. It is extremely effective, and you've all seen the hundreds of pictures of perfectly healthy plants that serve as witness to the effectiveness of that method. Remember though, you couldn't possibly fertilize this way when using a soil that is so heavy it requires you water in small sips to stave off the specter of root rot.
In the summer when all the temperate plants that snooze the winter away in an unheated garage, all the tropicals from the basement, and the dozens of display containers I scatter throughout the gardens & decks are actively growing, I couldn't afford the time to fertigate by hand each time the plants need a drink; so for summer I water with the hose & try to fertilize weekly as temperatures allow. It's probably almost as effective as fertigating @ every watering, but you could fertilize every 2 weeks if you're diligent & probably not notice a significant difference in any of the 3 intervals. I think if you start stretching it out beyond 2 weeks you'll start to miss potential that might be noticeable - and it's difficult to quantify lost potential because it's based on how much better a plant could have been. Often, growers think their plants are perfectly healthy and describe them as such when there are significant limitations in play that go unrecognized. Unfortunately, lost growth potential in plants is forever; it can never be 'made up for'.
For your peace lily, I'd bare-root if you're moving to the gritty mix from a heavy soil to avoid any issues that so often occur with dissimilar soils in the same container. Keep the roots moist at all times when repotting so they don't dry out. Don't worry if some of the foliage collapses after the repot - the plant should recover nicely and quickly leave you feeling rewarded for your efforts.
Al
Very Helpful. Thanks for the clarification.
Al: For non-cactus plantings, is the 5:1:1 mix better than the gritty (1:1:1) mix for typical plants? That is, if I am willing to change the soil annually, is 5:1:1 better than the gritty mix? If not, why not use the gritty mix for everything?
The gritty mix is excellent for cacti/succulents because it supports virtually no perched water to worry about (rotting roots). The 5:1:1 mix is still head and shoulders above most commercially prepared cactus soils, but not as good as the gritty mix because it does hold some perched water.
There is some confusion about the 5:1:1 mix's longevity. Personally, I only use it in containers that will go 2 growth cycles or less between repots, but that's just ME. Conifer bark, on a size for size basis, breaks down at about 1/4-1/5 the rate of peat and 'composted forest products'. Add the larger size of the bark particles, and it's much slower than that, even. Structurally, the 5:1:1 mix should outlast a peat soil by at least 6-7 times. In almost ALL cases, the plant needs repotting long before the soil is no longer servicable, something that can't be said about most soils based on fine particulates.
I use the 5:1:1 mix for my short term plantings because it's less expensive and easier to make. I realize I give up a small amount of potential, but I can live with that because plants are generally soo much more productive and healthier than those in heavier (more water-retentive) soils. Once you're used to the soil and your plants watering requirements, I think you would be pretty hard-pressed to discern any significant difference between the gritty mix and the 5:1:1 mix unless you get into trouble watering. The gritty mix is much more forgiving of over-watering, and growing in shallow containers.
If you use a soil that supports 3" of perched water in a 3" deep container, the soil will be 100% saturated after a thorough watering. That can't happen with a well made gritty mix.
Al
Thanks Al; that makes sense. I also have the impression from other postings that the 1:1:1 mix holds less water than the 5:1:1 mix, so for water-loving plants, 5:1:1 is the better way to go. Is that right?
Al, thank you seems so insufficient of a word for what you have brought to DG, but non the less, thank you so much.
I lived up in northern Ohio for 8 years and when I started a flower/veggie garden in ground I kept trying to teach the members of my garden club that you have to have light soil and I accomplished this by incorporating leaf humus in with rich top soil and horse manure. Within one season they could not believe how well the plants were thriving. They had drainage on top of clay soil that was the norm for the area.
Now I live in Florida and only have room for containers, I'm especially interested in growing tomatoes in grow bags (not the plastic ones). I’ve decided on grow bags for the breathability for the roots.
Do you think the material grow bags along with your mixture, to be ok and not too much aeration?
I'm going tomorrow to go out and start trying to find your incredients.
Jan
This message was edited Jun 17, 2012 6:45 PM
This message was edited Jun 17, 2012 6:46 PM
Just an update, I was so LUCKY today, the first place I call about the pine bark fines, carried them, they have all the other incredients.
The guy said they carry it because of all the raspberry growers use it to grow them in. I can't believe how blessed I am to have found this.
Should someone still be looking, you might could give them a call or email to see if they ship out of Florida. link below.
http://bigearthsupply.com/files/location.php
Jan
Hi, Jan. Thanks so much for the kind words - much appreciated.
The bags will work well, but if they are resting on the soil, you'll essentially be growing in mini raised beds, so you'll be able to get away with a soil much heavier (more water-retentive) than you could in a conventional container.
The relationship of the bag's design to aeration is sort of an obscure one. Technically, the bag has nothing to do with how well-aerated a soil is - primarily a function of soil particle size, but there's a twist that needs to be considered because it affects water retention, which DOES affect aeration. Because when these bags are resting on the ground the earth acts as a giant wick and pulls excess water from the soil, perched water isn't much of an issue. The Miracle-Gro soil that might have been much too water-retentive to allow you to water properly in a conventional container might be well-suited for use in a grow-bag.
Please make sure you give that some consideration when you formulate your soil.
I'll be around if you need help. Sorry I missed your earlier post - I've been terribly busy with my (bonsai) trees and gardens, as well as in the community.
Best luck!!
Al
Thanks Al
I'm planting to have the grow bags up on wire stands so the water doesn't pool at the bottom, as this will help the bags last longer. I was just so excited to find the pine bark fines, after reading that so many had problems.
Yes I totally understand being busy in the garden, when I lived up north, most of my time was outside in the garden or with my collies outside. I love the outdoors, but now that we are here it is limited to early morning or late afternoon.
Happy gardening to everyone.
Jan
Al:
This is a bit off-topic, but I'm curious what you amend your garden soil with (that is, for when you are not using containers) and other folks may be as well. Is there a thread on that subject you can direct me to?
This message was edited Jun 25, 2012 10:03 AM
happy_macomb sent you a pm so as to not go off topic here.
Jan
I usually use what compost I make around the base of plants and add a couple inches of fine pine bark as mulch every other year. That's it.
Al
Thanks, Al. I add compost too -- but haven't been adding the pine bark fines since they are a tad pricey here (I need a different source....). Many years ago I would add coarse sand as well (and peat) to break up my clay soil, then I heard that sand was frowned on; but where I added it my awful clay soil is much loamier. I was wondering how to translate your container principles to other situations....
Sounds like a request for more soil-building recipes, to me......^^_^^
>> Many years ago I would add coarse sand as well (and peat) to break up my clay soil, then I heard that sand was frowned on; but where I added it my awful clay soil is much loamier.
I had the exact same experience: "everyone" says clay plus sand equals concrete. But it does help my very heavy clay to be more friable.
(And then, maybe it is something like "it's easier to work some temporary structure into friable clay than into pudding". I wouldn't call it "good tilth" but it is a half-step into that direction.)
My theory is that sand doesn't do the same things that compost or organic matter do. And it seems to be most beneficial when the clay has almost no OM, silt, sand, grit or structure. The benefit is still noticable until the soil becomes fairly organic, with OM that does not disapear in a few months. Perhaps soil fungus or small root fragments start providing the micro-structure at that point.
Clay without OM has no life or structure or aeration, so it is no better for roots than mortar would be. It doesn't matter whether or not the mortar has sand - that clay needs lots of OM before it can ever be GOOD soil.
I wrestle with my cheapness and wheelbarrow to get enough compost into clay. The first year, I might not get more than 10-20% added. Probably 50-75% compost is what is really needed! OM just disapears into raw naked clay and sand while the soil life builds up and slow-digesting OM builds up. So my beds usually spend their first 3 years starved for "enough" OM.
However, WHILE it is still poor, clayey, low-OM soil, some sand or grit makes huge sticky blobs MUCH easier to break up with a fork, hoe or rake. And they stay broken up longer than sticky sand-free clay would. Like dusting sticky hard candy with powdered sugar: clumps don't stick as fast or as hard and air is more liekly to remain between peds. Without the sand or grit (or bark) the pure clay peds would deform and revert to airless puidding. I think that is the beginning of "tilth".
Perhaops a little "conc rete" nature is better than pudding-soup nature! If the peds and air channels are stiff enough to hold up, you might get som ne aeration and drainage for a season or tow.
Maybe I should say sand only adds friability at low OM levels - maybe it adds small scale stiffness (reduced pliability?) and tghatg aids strcuture and hence drainge? This is a new line of speculation, that occured to me as I'm replying.
With the addition of around 20% compost, sandy-gritty clay seems easier to work into peds that support a few air channels, than soupy-pudding-clay + 20% compost is. Probably, a few months after adding 20% compost, it is down to 5% OM plus 5% very hungry soil organisms.
I may be wrong, but it seems that way, the way I work with it. And sand or grit don't decompose in the first 6-12 months the way compost or peat does! Grit is forever.
Since Al turned me on to pine bark, I've been buying various kinds of mulch and screening it. That seems even better than sand and grit at opening up heavy clay. Bark shreds are longer than grit, and a bark shred has a better aspect ratio (longer than it is wide) than sand grains. They don't find it as easy to pack tightly.
And I imagine that bark can "absorb" a little clay. A few 1-5 micron clay grains can probably nestle into pores and cracks in bark chunks. At least that keeps SOME from being transported into air gaps where they wsould plug drainage and aeration. Sand and grit can't do that.
It might be true that if you mixed clay with sand and then soaked the result and pounded it flat, the clay would "run" and fill every gap and the result it would have no more air than adobe.
But if you mix clay with sand-grit-bark, not-too-wet, fork them up a bit in the raised beds, tamp very lightly so only the surface compresses, and then avoid soaking or pounding flat, they might hold up enough to sustain SOME air channels for a season. At least until the next turning when you add more compost. People who know good soil might not call that structure or tilth, but it's the best I've got until roots start upholding the soil and worms maintain the infrastructure..
I would urge you to consider even the cheapest, crummiest bark mulch (properly called logyard waste or "Home Depot mulch") over using all sand. Don't use cheap mulch in pots, but it adds coarse, slow-disintegratin g OM to outdoor soil. And a cubic foot of bark is much lighter and cheaper than a cubic foot of sand!
And crushed rock in 2-4 mm sizes is better than any bagged sand I see for sale, which is usually 50% fine sand (0. 2 mm, 0.1 mm and smaller).
The kind of improvment that I talk about is not changing "good" soil to "best" soil. It is about changing "unusably bad clay" to "poor but usable soil" in one year, cheaply.
Then I keep adding more compost and mulch for a few more years, and it becomes what I think of as "pretty good soil!!!"
If I ever work with actually GOOD soil, my rating system might chnage. Right now I am an easy grader.
Thanks, RickCorey_WA; what you are describing is my experience as well.
Thanks very much. The IDEA that clay should wash into any air channels or voids and plug them solid makes SENSE, bujt it has not seemed tgo work thaty way for me.
I see I got very verbose as usual. The short form is: keep adding compost until the soil is good.
MAYBE sand or grit is helpfull in the early stages if your clay really has no silt, no sand, no particles.
It seems to me that the way I work, it does help avoid the rapid return to "pudding soup".
Classically, "good soil" was supposed to have some of every particle size.
Tapla, what do you use to screen the turface, pine bark, etc. (I know you use hardware cloth, but HOW do you do it)? Do you build sieves for that? Do you have photos of yourself at work? I would think that process would be slooowwwww but you have indicated it isn't.
Lol - My secret is that I have my guys at work screen my Turface in the winter when we're not too busy (I own a glazing contracting business [glass company]). Here is what I/they use (see below).
I get prescreened bark and granite, but I do screen those over insect screen to remove the dust.
Al
If I could jump in here...
You could build a screening table, if you're inclined to do that. The plans are pretty simple. Build a frame of 2X6 OR 2X8 square just a little bit bigger than whatever cart or wheel barrow you plan on using. Build another table frame large enough for the cart or barrow to be pushed in place underneath. On what would be the front end extend the frame about 4" to 6" to be a pivot for the inner screen. Drill a 13/16" hole with the inner & outer frame aligned. Install 3/4" pipe just a bit longer than the outer frame and use pipe caps to close it in place. Have a second wheel barrow or cart at the front to dump the "larges" into as you sift the bagged material. I would use 3/8" or 1/2" hardware cloth, only problem is finding the 3/8" so use 1/2" because it's also a lot cheaper.
A couple notes & something I forgot before. Make sure you extend the outer frame lone enough so when you dump the screen it will clear the frame and be easier to empty. Make sure the legs, 4X4 PT posts, are a comfortable height to work with, and attached to the outside of the outer frame, so your work area is right in front of you, and you're not stretching across to get stuff that gets away... On the "tail" of the outer frame attach a 2x4 from side to side to create a lip for the inner screen to sit on while you're sifting.
Use garage or fence type door handle to attach to the inner frame to dump it. If you want to make a second frame with different size mesh, you could do that and just pull pipe and switch out screens.
I hope this helps...
tapla,
You kind of beat me to it but your pictures are great. I just added the outer frame and dump feature to it.
Kevin
Kevin: I'd love to see a photo -- I'm having a hard time visualizing this. Might be the hour, of course!
Tapla: Love the photos. Wish I had the staff!
Happy: This was more of a concept for a screening table than what I actually built. Tapla's pictures are great and you could use them to build my table. If you have some woodworking experience it would help greatly. It's all just simple cuts with a table saw and simple joinery.
On pic #1, it shows the simple inner frame with 1X4 white boards. Measure to size you need for your carts or wheel barrows. Photo #2 shows the half-lap joints. You would you these joints to make all your framework. For the outer frame make the inner width about 1/2" larger than the inner frame so it will just slide in & out when you dump the inner frame "larges" that remain after sifting. I would use 2X6 to make the outer frame because it will hold all the weight of the frames and the sifting media. 4X4 Pressure treated posts would make the legs. I have air impact tools so it makes my work a lot easier!!!!
In Photo #3 it shows the handles on the side of the frame, on mine put them on the upper side of the frame so it will nest in the outer frame when you're sifting. They will be on the "tail" end of the frame so they will be out of the way while you're sifting.
For the brace to hold the inner frame in the outer frame just use some of the extra 1X4 white board the width of the outer frame. Attach it to the tail and side frame leaving about 1" creating a lip to hold the inner frame inside the outer frame.
With the inner frame built & sitting inside the outer frame measure and drill the 13/16" hole through both frames to hold the 3/4" Galvanized pipe to use as the hinge. Buy 2 caps for the pipe that way you can pull the pipe out to change inner screens when you sift different materials, just build another inner frame. Use your first frame as a template for subsequent frames.
If you still are having any problems give me your dimensions and I'll draw up a set of plans for you. One of the other real important things to remember is to make sure you get straight board material. It's a real pain to build with wood that looks like a propeller!!!
If you have any questions please send me a d-mail....
Kevin