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Lettuce Raft System

Posted by wordwiz ( on
Fri, Jun 10, 11 at 16:54

I wanted to try this after seeing pictures of a few systems (medium to large size) that looked enticing, not to mention inexpensive to build and relatively easy to maintain.

Found a cheap source for Styrofoam (a Drywall company), had a 24x30" box and some 4-mill plastic to line it with. I also have several shop lights, a good size air pump and lots of soaker hose, plus a few left over horticubes, net pots, lava rocks, nutrients and seeds. Basically, it was only going to cost to run the 4 40-watt bulbs.

Mixed up some nuits (Garden-Tone dissolved in water) and adjusted the tub of water to about 800 ppm and the pH to 6.0.

As I am apt to do, I screwed up by trying to use some Fish Emulsion to boost the N level. Resulted in a lot of foam and slimey gunk on the roots. Emptied the water, washed off the roots and restarted. The plants were slow to respond at first but maybe a week ago showed signs of survival. I checked them this morning and they are 4x the size they were a week ago.

I have room for three 12' long trays of plants (at the spacing I'm using that would mean 216 plants. I would love to get the grow cycle down to six weeks.

Next - to learn how to grow enough tomatoes to go with the lettuce! Then tackle cucumbers. And, can one grow carrots hydroponically?


Follow-Up Postings:

RE: Lettuce Raft System

That is a ton of plants Mike! Do you do hydroponic gardening for a living, or are you just a vegetable donating philanthropist?

I have never grow via a raft system, but I have been interested in the concept. Would be cool to maybe see some pics of what the system looks like!

P.S. As for the carrots, I hear those work well with perlite as a medium because it provides the right kind of thickness for the carrots to spread through.

RE: Lettuce Raft System

I used cocoa coir for a medium for carrots. It worked well. I used a drip system to do it by planting several in a 14 gallon rubbermaid tub and running a drip line over the top. They took a long time and the carrots were HUGE. They were also very misshapen. But, they tasted great and were perfect for grilling.

RE: Lettuce Raft System


I don't have enough plants in it to post a good picture of the system, plus it is just an experimental ghetto box now. But here is a picture of some of the lettuce and a general look at the raft.

I don't know how long the plants have been in the system, but two weeks ago the plants in the corner were about the size of the one on the right.

Not sure if it is good or bad, but the same type plants in my backyard garden has their leaves all pointing up. Plus, even though the latter plants are a bit taller, their bottom leaves are not quite as large.


RE: Lettuce Raft System

Hey Mike. Judging by the lengths between nodes, you don't have enough light. I would say it's also why it's limp. I would venture to say the leaves aren't as thick as those in the backyard garden. If you pick a leaf, you will probably find it to be a flimsy, less crunchy texture. I speak from experience.

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