I have a table my BF's father made that was essentially a box on legs with a glass top. They had sand and shells in it - was very lovely, but it had its day and he gave up on it last year. I draped a blue tarp over it (glass top is long gone) and some old windows over it this spring. Sort of a standing cold frame/greenhouse. now I am also soaking plants in it. I have seen some folks self-watering vegetable tables. I am thinking about growing lettuce there. Cut it down when it's nice and short and tender. What do you think?
A.
Hydro, EB, Raised bed, Container?
I"m sure it would work up to a point. If the water heats up too much the lettuce won't do so well but if you're in semi-shade that will help a little. Or change the water daily to help keep it cool.
I used to grow letting in a 6" pvc pipe, lengthwise. I cut holes in the side every 8" or so, filled it with perlite, stuck in lettuce plants, and would water at one end filling the pipe. Once it was filled I'd let the water out the other end from time to time. Although I did that to grow Romaine and loose-leaf types I'm sure you could grow cut-and-come-again lettuce using your water table in a similar way.
Shoe (tired of this heat wave already)
After several months, everything I've tried in standing water trays has grown well. My picture shows peppers in the foreground, hotter ornamental peppers behind them, and a glimpse of some Brussels Sprouts that the bugs got to before I could dust them. My method worked ok as an emergency measure, but if I continue this in future years, I want to find some sturdier water trays. I found that the flimsy seed trays don't survive if you step on them!
Heyyy Twiggybud.........hits me agin!!! I built some waterbeds 5 or 6 years ago and am just now starting to use them. Yep, moving right along. I removed the stacked container grow poles from the four corners of these 3 platforms and set them up to be mini greenhouses in winter or for shade cloth in the summer. Also covered the platform beds with doubled up black plastic sheeting so that the beds can hold up to 11/2 inches of water. I have an adjustable relief gate so I can vary the amount of water the beds will hold depending on how many and what kind and size of plants I have on the platform. I dont wont standing water in the beds so I can adjust them so the plants will suck them dry and eliminate the possibility of mosquito's. The beds are on the same automatic watering system as the grow poles were before I removed them..........four quarter inch water lines for each platform but I have goof plugged two of each platforms quarter inch lines at present. So with the adjustable relief gate and adjustable water lines I can adjust the amount of water each bed gets individually. I am a-fixing to load them suckers up with containers and see what happens. Wish me luck!
Very impressive, Jay! Let us know how they work.
That really is some nice work.
Twiggybuds, Ive done what you suggest for a long time. It's so hot in my area that I would be watering twice a day the "normal" way. Ive found if the saucer (whatever that happens to be) is of the right depth, not too deep, the roots dont rot. I just keep the pots sitting in about 1 to 2 inches of water and the plants never have to do without. It's a great solution, I think to the watering problem. Ive used a kid's wading pool, an under-the-bed storage box, kitty litter pans and various "saucers" that hold many pots at once. I think that thing of never allowing pots to sit in water, got started with house plants where the light is almost always low which would encourage rot. With outdoor light, sun, etc it has always worked well for me. you go girl!!!
Someone left a link in another post, so I came here out of curiosity. I didn't take the time to read the whole thread, only scanned it quickly, so don't know if anyone ever took the time to explain WHY this is working for you, based on physiology. I did see a lot of suppositions upthread about why it might work or 'what's going on' that were incorrect. If you already figured it out, or someone explained it, I won't bother. I'll watch the thread to see what you think.
Al
Go ahead Al. Do the physiology thang.
The roots produced under hypoxic conditions or under water are quite different from those produced in container soils 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.
Al
Open water beds and earthboxes (self watering containers) are very similiar with plant roots able to reach directly into water or highly saturated grow mix. Do you see any advantage, one over the other?
Al, glad to see you lending your expertise to this thread! What do you think of the following summary. Does it make sense?
I put plants in containers about 12 inches high with holes in the bottom. These sat in troughs containing at most 1 inch of water. (I watered from the top once or twice a week and added water to the trough if it ran out.) Thus I believe that the bottom inch of soil mix in the containers was saturated, with capillary action raising the "perched" water level (your phrase in another thread) another 1 or 2 inches at most. (This is a guess from how the soil appears when I empty the container.) Thus, the roots, which start perhaps 1 inch below the surface, can reach down 8 inches through normal soil until they reach the two inches of damp soil and the bottom inch of saturated soil (your hypoxic condition?). I don't see any cause for concern, here. When I removed the plants at the end of the season, there appeared to be plenty of healthy roots in the 8 inches of normal soil. If they reach further into the damp or saturated region and form what you call aerenchymous tissue, wouldn't that still collect water and food for the plant?
I'm also confused by the etymology of "hypoxia". Hyper comes from a greek root meaning "too much" not "lack of". Shouldn't the lack of oxygen be "dysoxia"?
The root for hypoxia is hypo which means less than. Hyper means more than. It was not noticeable because oxygen begins with an o.
I have a question for Tapla.
How high will water wick in a medium? I want to wick water 48". What kind of medium would I use?
I am looking at building some 48" tall tower gardens. I would like to be able to water these from a standing water source.
I want to thank you again for your very informative posts. Each one is an education.
We are so lucky to have you spend your time writing for our edification.
Paul.
very interesting thread! the things you find while looking for other things... :-)
A suggestion for those looking for small but sturdy trays... the black "concrete mixing trays" sold by Lowe's are working well for me and have stood up to a couple of years outside so far.