CONTAINER SOILS - WATER MOVEMENT and RETENTION XXII
9 years ago
last modified: 9 years ago
Featured Answer
Sort by:Oldest
Comments (1K)
- 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked tropicofcancer (6b SW-PA)
Related Discussions
Container Soils - Water Movement and Retention XVIII
Comments (229)When it comes to root health, pots with gas permeable walls carry the day. Terra cotta clay pots are better than plastic or vitrified clay pots and fabric pots are better than terra cotta clay. The reason is greater gas exchange through container walls and the fact that an increase in gas exchange comes with an increase in evaporative water loss, which can be a lifesaver when using water retentive media. There will still be a PWT in these pots, and for any given medium it will the same ht in a pot with rigid sides as in the fabric or air pots at container capacity. Container capacity is a measure of how much water the grow medium in a pot or container holds at the moment it has stopped draining after having been watered to the point of complete saturation. The ht of the PWT and how long it affects root function is usually key/critical in determining what opportunity a plant will have to realize as much of its genetic potential as possible (within the limiting effects of other cultural influences). The factor that most affects the ht of a PWT is the size of the particles from which the medium is made. So, reducing the duration of PWTs limitations increases the opportunity for plants to realize a greater measure of their genetic potential. But wait! There's a more important consideration. If you place your fabric containers directly on the ground/soil, from the perspective of hydrology it changes the fabric container to a raised bed; this, because water is free to move through the fabric between the grow medium and the earth, with the earth acting as a giant wick. This means, because of the increase in the force of adhesion in the mineral soil beneath the pot (due to a mineral soils much larger o/a surface area on a per volume basis), water in the soil will be pulled downward with enough source to overcome the capillarity holding it perched in the container. As long as you don't place the fabric container on coarse sand, peastone, or other large particles, the earth will likely pull all perched water from most media one is likely to use in a container. I've mentioned this and the fact that healing in your pots situating them directly on top of soil turns them into raised beds. the only caveat being it's essential that there is a 'soil bridge' so there is continuity of the soil column between the soil (earth) and the grow medium in the container, through the drain hole(s), so water doesn't have to jump an air gap to exit the container. This applies more to pots with rigid walls and is not a factor when discussing fabric containers. Al...See MoreContainer Soils - Water Movement and Retention XVII
Comments (202)Exactly, the paper i pasted from describes the same phenom you have been describing for over 10 years. I have always raged that the big greenhouse media suppliers claim that 30% perlite into a peat is a high porosity mix. And so many growers prefer short squatty containers [helpful for blow over prevention but nothing else] Container Geometry is almost as important as the mix. i remember in 1984 I took a 400 level greenhouse management course at University of Delaware. The prof soaked a rectangular sponge and held it by the edges parrallel to the sink flatwise and let water drain, then he rotated the sponge on the shorter vertical axis and more water drained, when that free drainage ended he then rotated the sponge vertically in it tallest plane and more water drained. When I read your suggestion about using a draping shoelace as draining wick to lower the PWT the distance of the wick, I shouted YES at the elegant simple brilliance. In 1977 I grew a marijuana plant in a milk crate full of gravel, the stalk was over 2 inches in diameter [no different than growing in glass.] BTW, in your gritty mix what are the ratios and actual particle size for each component? I would think to use slightly larger particle sizes than i think you were using and i would probably consider using zeolite or a calcined DE or calcined clay. BTW, Ep minerals makes several absorbents both DE and Clay, Calcined or regular as various spill absorbers available in any auto parts store. 5o pounds for about 10 dollars. Don''t know the particle sizes but likely need to be screened to eliminate the fines. The clays are generally calcium bentonite and not sodium bentonite so less sodium and less swelling. I beileve Arcillite and Tuface are calcium bentonites. I was just thinking that decomoposed granite and even bark add no water holding capacity but with DE and Proper sized ceramics you could add more waterholding capacity but still maintain the airspace. The airspace in the ep mineral clay was pretty low when I measured it last, but I did not screen it. Somewhere I have a spreadsheet with AFP, WHC, TP, TPv, etc for over a dozen components and mixes. I have run quite a few in both 16 oz and taller 32 oz cups, [1 liter exactly when filled to rim overflow which makes that size intuitively easy for all the math. I think i found your posts about 3 years ago and then lost them. Am I correct in thinking you have some water release curve data around somewhere. Someone posted some WRC showing that Axis DE or perhaps the Axis clay media held huge amounts of water but easily released over 75% to the plant. TI can not find that post. I was actually searching for Vertical hydraulic conductivity, Capillary Rise and Capillary rate and wicking when your links showed up. The axis DE is like $90 a bag for 50 pounds so i think I could more cheaply reproduce from other products but have to screen. where I live in idaho, there is a Celatom DE plant less than 60 miles away, 2 zeolite mines, a sodium bentonite mine, WHC and Airspace mid 20s in the 2 larger particle sizess. Also the best white pumice [Hess] source mine a few hours away. I had hoped better water holding capacity. I plan on rerunning all the mixes again in a few months now that i have more standardized my process using multiple cup sizes, some of them tamped or shaken to settle, some top watered, some bottom water, measure distance of subsidence if any. I also have a vegetronix tensionometer now and will take additional measures at various depths to measure the exact tension and also verify depth of pWT which i can usually see through the transparent cups if I use a marking dye and saturate from below. Anyway I will share those spreadsheets in the near future If i were to guess, you have some sort of plant and soil science background or some civil engineering background and a love for plants. At any rate, your explanations and examples are some of the best I have ever come across, and your shoelace suggestion is brilliant, truly. i read so much WRONG advice or the wrong analysis for reason why something works or does not work. it is refreshing to come across accurate information Garret Goyette...See MoreContainer Soils - Water Movement and Retention XVI
Comments (164)Hi Al and others, I would appreciate advice on saving sick/dying Picea glauca, in pic.1, please. I bought it on post Xmas sale and it was ~50cm tall, looking healthy, with very bushy top. I repotted it without much root cleaning to keep most original soil with fungus, which I read Picea, like other pines, needs. I planted the rootball with old soil into gritty mix, mostly pine bark fines with seramice, with a bit of gravel, see in pic.2 very "gritty" indeed :); trunk is ~1/2" at the bottom). I used a biggish pot to let it grow freely for a year or two. I also cut the top to encourage lower branches growth but it never happened. Water it when the pot feels light, ~ weekly (it is early autumn here in Sydney) by bottom watering in a bucket, then drain well by keeping the pot at ~45 degrees for a while. Use diluted Nitrosol liquid plant food every two weeks. Keep it on sun for 2-3 hrs, then half shade. Despite all my care (or coz of it ? :), the picea never showed any new growth but started developing warning signs for last 2-3 weeks. Those few thin branches started dying. Their stem turns from brown to greyish-green and gets soggy before dying. See in pic 3&4, that branch in front which is dying now, with grey stem. Other branch died a few days ago. Only three normally looking branches are left. But I am afraid they are facing same fate. Anything I can do to rescue my future picea bonsai at all? Thanks and cheers, Sergey...See MoreSoil questions with pics
Comments (1)I'd recommend starting from scratch -- you're likely to get much, much better results with a high-quality container mix, and the original post in this thread will provide all the information that you need to assemble one: CONTAINER SOILS - WATER MOVEMENT and RETENTION XXII...See More- 4 years ago
- 4 years ago
- 4 years agolast modified: 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked Gregório Miranda
- 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked tropicofcancer (6b SW-PA)
- 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked tropicofcancer (6b SW-PA)
- 4 years ago
- 4 years agolast modified: 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked Gregório Miranda
- 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked tropicofcancer (6b SW-PA)
- 4 years ago
- 4 years ago
- 4 years agolast modified: 4 years ago
- 4 years ago
- 4 years ago
- 4 years ago
- 4 years ago
- 4 years ago
- 4 years agolast modified: 4 years ago
- 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked tropicofcancer (6b SW-PA)
- 4 years ago
- 4 years agolast modified: 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked tropicofcancer (6b SW-PA)
- 4 years agolast modified: 4 years ago
- 4 years ago
- 4 years ago
- 4 years agotapla (mid-Michigan, USDA z5b-6a) thanked tropicofcancer (6b SW-PA)
- 4 years ago
- 4 years ago
- 4 years agolast modified: 4 years ago
- 4 years ago
- 4 years ago
- 4 years ago
- 4 years ago
- 4 years agolast modified: 4 years ago
- 4 years agolast modified: 4 years ago
- 4 years ago
- 4 years ago
- 4 years agolast modified: 4 years ago
Related Stories
CONTAINER GARDENSContainer Gardening Basics: The Dirt on Soil
Learn the types of potting soil available and the best mixes to help your containers thrive
Full StoryGARDENING GUIDES10 Solutions for Soggy Soil
If a too-wet garden is raining on your parade, try these water-loving plants and other ideas for handling all of that H2O
Full StoryGARDENING GUIDESHow to Stop Worrying and Start Loving Clay Soil
Clay has many more benefits than you might imagine
Full StoryGARDENING GUIDESHow to Pick a Mulch — and Why Your Soil Wants It
There's more to topdressing than shredded wood. Learn about mulch types, costs and design considerations here
Full StoryGARDENING GUIDESGreat Design Plant: Anemone Canadensis Adds Pizzazz to Water’s Edges
Plant Canadian anemone along pond, lake or stream edges for a splash of white flowers in late spring
Full StoryCURB APPEALCrazy for Colorful Cones: 5 Container Plantings Beyond the Bowl
Give even a small garden an exuberant vibe with hanging cones overflowing with blooming beauties
Full StoryFARM YOUR YARDHow to Grow Vegetables in Containers
Get glorious vegetables and fruits on your patio with a pro’s guidance — including his personal recipe for potting mix
Full StoryGARDENING GUIDES10 Dazzling Winter Container Designs
Get inspired by these ideas for festive arrangements in outdoor pots and planters
Full StoryGARDENING GUIDESHow to Install a Drip Irrigation System
Save time and water with a drip watering system in your vegetable garden — a little patience now will pay off later
Full StoryLANDSCAPE DESIGNHow to Design Your Landscape to Slow Down Water
Putting the brakes on stormwater runoff is the first step in sustainable water design
Full Story
Bill