do a search on raft systems. basically you build say a 4'x4' reservoir and float a piece of insulation board in it. in the board cut your holes so the pots sit in them and in the water below.
From what I've read (haven't done it myself) its very effective for growing lettuce.
good luck.

I would think that maintaining the nutrients in X number of cans would be pretty time consuming and tedious. I would suggest building a simple NFT system using pvc rain downspouts from HD/Lowes. Drill holes every 8", set the downspouts on a slope so that it drains back into the nutrient reservoir (or rain gutter that drains into reservoir). You will need a small pond pump and some tubing. You could take the 10' downspouts and cut in half and could build a 5' by 4' table with 6 channels spaced around 8". Take a look at the small nft systems on the American Hydroponic webpage for ideas. There were also some small nft system pictures posted on this forum with exactly what I am talking about.

Here is a link that might be useful: American Hydroponics NFT System

Read here for a raft system, the type I think you are trying to describe.

Here is a link that might be useful: Hydro Raft Lettuce

Thanks grizzman, i'll come back later and try the search. i tried 'lettuce' and 'gutter' but wasn't finding what i was looking for.

backyardhydro-this Mr. Masako just uses a tsp of miracle grow per can-how easy is that! But i don't want a bunch of little cans everywhere so the raft system seems like the right way way to go-for me.

willard3-great link, thanks. Amazing what they can do in 30 days with precise control over the environment. Probably i will be a little more relaxed in my approach but plenty to take away from the site.

appreciate everyone's help.

mauirose,

I've had good luck with my raft system, which is 2' x 4 1/2'. Since last October it has produce 8 crops, which have provided enough lettuce, continuously, for two to three families plus a couple guinea pigs. I have been working with the original nutrient solution since October. I just dumped it, cleaned the tub liner and replenished the solution yesterday. I aerate the solution with a inexpensive pump. I check the pH and EC, but I think one could get by without checking the EC. I do add some make-up nutrient solution once in a while, but mostly I check the height of the nutrient solution, and when it gets low, I add tap water. In short, lettuce has been easy.

A word of caution when growing lettuce: If it's hot where you are, grow something else!

I've tried every trick in the book and have always been humbled by heat. Lettuce bolts when it gets too warm!

freemangreens is obviously correct about the lettuce bolting in hot weather.

However, if you are not a lettuce snob, like I'm not, and if you are growing in a greenhouse, like I am, then it is possible to keep lettuce on the table through the summer--even in Tucson, BUT one has to keep after IT.

As I indicated earlier, I'm using a raft system; it holds about 50 gal of nutrient solution. I hold the solution at about 73 F; the daytime air temperature ranges between 80 and 90 F.

The lettuce bolts sooner at higher temperatures, but it also germinates faster (3 days). I'm transplanting the seedlings to the raft in 19 days, and start harvesting (cutting leaves) in 28 days, and then I have about three or four weeks of harvesting before I remove the plants. As soon as I transplant to the raft system, I plant the next crop in rockwool, which I stash under the bath, where it's shady and a bit cooler, for three or four days until the seedlings are visible.

Is it easer and less expensive just to go to the supermarket and pick up lettuce for a buck a head? Yeah, but I find it very satisfying to walk out to my greenhouse almost ever day at lunch time and pick my salad.

I've built an aeroponics system for my lettuce, but I'm not even getting out of the seedling stage. My seeds a sprouting in two to three days and growing tall very fast and finally falling over. Can any body tell me what is causing this?

I have attached (hopefully) some pictures of my current starters that are looking just like the last ones. The stems are very light and almost transparent. One of the stems is already falling over.

These pictures was taken a few minutes before the sun came up so you can't tell, but I've moved these to the brightest room in my house. The seeds on the left are grown in coconut shreds and the right is a starter soil.

BTW, I didn't put seeds in every cup. All but one seed has sprouted, so thats not a problem. The Room is about 68 or 70 degrees. I was told to grow the seeds inside for a week to 10 days, to get them started.

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Calvin_09;
I haven't grown lettuce before, but from looking at your pictures I would wager either:
you're not planting them deep enough, or
you're not getting them enough light.

I doubt it's the not planting enough. I don't plant. I lay the seeds and press gently. I think grizzman's right about the too little light. It's the first thing I thought when I saw the post. Lots of light. Don't need any nutrient for the first few days either. I start in coco coir. Notice you can see the seeds pretty well. In case you are wondering, that is wool felt used to keep the coir moist. I just water the butter containers on the sides. Don't put the wool felt all the way across the bottom or roots will grow into it if you don't transplant fast enough. Notice I'm in direct sunlight, too. Germination took a few days. Be sure to provide a cover if it rains.

Thanks guys,
It looks like I'll have to move everything outside. High temps are running in the mid to high 80s here in Atlanta. Is that too hot? If so, any tips to deal with it?

I wasn't expecting to run into problems until the hydro stage of growth, and I'm paying for my lack of research on the seedling stage now.

I really appreciate the advise.

Thanks
Cal

well i am moving along with my little experiment. i just finished building the raft frame and drilling holes in the insulation board so it should be just a few more weeks until i have lettuce. i based my raft system on a Univ. of Florida publication which i'll attach in case anyone is interested.

joe.jr i like your germination set-up! Can you explain the transplant process? i don't see the coir pre separated and it doesn't seem like it will be an easy job to remove just one seedling at a time because of the way the coir forms a mat.

i am thinking you will be moving individual plants to net pots but maybe you are working with a different design?

dennyg thanks for sharing some of your techniques. i don't think bolting will be an issue for me here, hasn't been so far growing in the ground unless i do not water sufficiently.

Here is a link that might be useful: Something like this

Transplanting is very simple. I use this germination method for hydro and soil, both. As soon as a true leaf is showing I transplant. Lettuce bounces back very well even if you do a little root damage (though you should try to avoid it, of course). I simply use a spoon to scoop out the plant or sometimes a few plants at once. I submerge the roots in one of those bowls to get the coir off if I need to, but I don't normally need to since I use coir as a medium for hydro and obviously don't need to remove it for the soil. I always submerge them if there are two or three plants intertwined, though. It's better to let them separate by gently swishing them around in water than to pull them and break some of the roots.

I grow the purple lettuce for decoration as much as food. Ever let that stuff go to seed? It's beautiful! Gets 3 - 4 feet tall and has yellow flowers on a purple leaved plant. On top of that, you can harvest one plant's worth of seeds to have thousands available. I've not had any problem with germinating lettuce seed from plants grown from commercially sold seed, either. I have with tomatoes and peppers and such, of course.

Last, my hydro isn't what most people use for lettuce. I've done the rafts. Seen NFT. Feel the rafts are a pain for cleaning and maintenance compared to just using a drip system (aka plastic spaghetti jars with small holes in the very bottom to slowly release nutrient) in a 14 gallon container with coir (chunk and fiber mix). I also reuse my coir several times. Since my wick systems are working so well for my potted peppers, I think I will start trying to use the same system I use for germination to grow the lettuce to maturity. I'll just use deeper coir, of course, like in the 14 gallon containers.