In a discussion on one of the forums some one posted this link.
Non-circulating Hydroponic Methods for Growing lettuce.pdf
Which got me to thinking. I have a quarantine system that when I have new fish that are being fed high protein feed, I’m getting rather high nitrate levels but that system isn’t really set up to hold a lot of plants yet. So this might be a way to grow more plants when the nutrient levels are high enough to warrant a water change. I only have some much air capacity to do actual floating rafts but if I can grow without having to run more air or pumping or plumbing, I might be able to set up remote DWC beds where the sun is good. (The good sun spots change quite a lot depending on season here too.)
So I decided I should run a small test. I set up a couple bus tubs. I had some extra 1/2″ foam that I cut to fit and put 6 holes in each for the net pots.
Now I’m not convinced that totally passive will give adequate results with AP water. I’ve added a couple small air stones into one of the tubs so I can compare.
Anyway, each tub got filled till the water was into the bottom of the net pots. Then I placed peat pellet seedlings of all the same variety of lettuce from the same batch of seed and planting day into the net pots.
Here is the picture after it was set up.
Non recirculating hydroponic test with aquaponic water
Hey TC, Anything different/interesting going on between the two setups?
Yes, as a matter of fact, there is a marked difference between the results on the two set ups already. I’ll have to take some pictures and post them later.
It has been less than two weeks and the aerated bin is definitely doing far better though starting to show possible signs of deficiency while the non-aerated bin is kinda languishing.
Thanks. I guess that was somewhat expected, and unfortunate the still-water bin isn’t doing so great.
Let me see if I can post some new pics.
What are the final results?
Well, the picture isn’t all that decisive but the bin with air did look a bit better at the end. This test was done in cool weather so there wasn’t much of a problem about the water overheating. I think in hot weather or a sunnier location it could be more of a problem having the lettuce roots in water without aeration. Having the air gap between the bottom of the foam and the top of the water is very important if you are going to run with out supplemental aeration. In shallower containers with not enough room or in situations where the foam is floating on the water instead of suspended above it I would say the aeration is mandatory, especially if you are trying to grow out a salable product rather than just growing a little lettuce for yourself.
Thanks TC for taking the time to do this and post the results it is very helpful for newbies like myself – I have read tons of your stuff on two forums and your site, just wanted to say thanks for all the help along the way and make sure you know it does matter.
🙂
Bart