NFT Lettuce

[OChydro]

Lets talk NFT.

I recently started my bibb lettace in rockwool the same way as described in my dutch bucket squash thread. I have transplanted them into gutters. I went ahead and sprang for the CropKing gutters, all other parts are HomeDepot issue.

From what I have read the cubes should not be touching the bottom of the gutter. I think I may have transplanted a bit early as the roots were not busting out of the cube. I read that if the cubes touch the bottom of the gutter they will stay too wet and I will get root rot. My plan is to reset them in the gutter, keep them off the bottom and wait for the roots to reach out for the gutter bottom. To keep the cubes from drying out I will just hand water them everyday or every other day to keep them moist. Since this is a small system, 1 gutter with 5 in the future, it won't be a problem.

If I leave the next batch in my high tech germinator pan an extra 2 to 3 weeks I would think the roots would be busting out. Again the only problem I see is that the roots still won't be dangling into the gutter flow and I will still have to top water them. I could always build one of the upspraying starter units which will develop the dangling roots I need but this is a pain, I want it to be simple. I'm not sure how commercial growers solve this problem but finding out would answer the question.

I am using the same reservior for my dutch bucket and NFT.

[Luches]

Hi OChydro,

Rockwool isn't exactly the best solution for lettuce in NFT, not for germination and for nursing neither. Actually roots tend to spread laterally in rockwool. I recommend special Lettuce cups, filled with a mix of 1 part Vermiculite and 3 parts of Perlite (both fine grade).

Also, (even if using rockwool) you can't transplant until the roots have grown long enough to reach the bottom of the gully! Just wait until they are at that stage, anything else is pointless (no offense).

PS: use adequate nutrient for lettuce and the very adequate concentration to grow your seedlings, (starting with PH corrected, low ppm, RO or even distilled water for germination and beyond) otherwise you have delayed root growth and loose "vital" time in the ongoing operation.

If you need pics of the lettuce cups, nutrient requirements or other hints, just call in again...

Cheers,
Luches

[OChydro]

Thanks for your reply. Pictures of the lettuce cups would be great but I'm not sure how I would use these in my gutters as they have 1 inch square holes, would they fit in my gutters? Please let me know.

[Luches]

Here is the cup with the size. Up to you if you use them and make them fit. As these are bigger than 1' it shouldn't be a problem.
Best is to have the cups in a shallow nursery with a continuous flow of water respectively week nutrient solution (like we have).



Here they are in action in the gullies.

[GpsFrontier]

From what I have read the cubes should not be touching the bottom of the gutter. I think I may have transplanted a bit early as the roots were not busting out of the cube.

Well ya, with a NFT system the roots should dangle in the flowing stream of nutrient solution. The dangling roots then wick up the nutrients to get the moisture they need. They also wick up the moisture into the growing medium, keeping it moist. But if the growing medium is touching this flow of solution it will become saturated depriving the root system of oxygen and or air. Some plants don't like keeping their feet wet as much as others. From what I understand Lettuces is a cool weather, low light, water loving plant. So they should not mind there feet being wet as much as others might, but you don't want to deprive them of oxygen/air either.

If you have the capability to adjust the water height, you can raise the height until it touches the bottoms of the growing medium and the roots start dangling down. But you would want to use a timer and set it to go on/off in intervals like a flood and drain system so that it's not running 24/7 as it does in the NFT. Then when they dangle down far enough you can convert back to the NFT system.

If I leave the next batch in my high tech germinator pan an extra 2 to 3 weeks I would think the roots would be busting out. Again the only problem I see is that the roots still won't be dangling into the gutter flow and I will still have to top water them.

Well, you could possibility build something. I am thinking of something like using 2 stackable Tupperware containers, so one will fit inside the other but not go all the way down. Then cutting holes to fit your growing medium in one of them. Place the seeds in the growing medium, and the growing medium the holes. Then place the container with the growing medium inside the other one, and pour in just enough water to keep moist. This should hold the growing medium up so the roots can dangle out the bottom, and using the two containers should hold enough moisture so it wont dry out fast. It doesn't need to be Tupperware, but the idea is to have one container fit inside another so that it will hold the one with the growing medium in the air and provide the space underneath for the roots to dangle down. You could probably find something usable for this at the dollar store.

I'm not sure how commercial growers solve this problem but finding out would answer the question.

I have not looked into that at this point. Although all commercial operations usually have greenhouses devoted to germinating seeds and complete control of that environment, including air temp, lighting, humidity, nutrient temp and delivery. This way they have a consent supply of plants the right size to replace the ones that were harvested, so there is virtually no down time and maximizing efficacy. To them building an automated spray system would be nothing.

[GpsFrontier]

I was looking for something else when I ran across these pictures of lettuce being grown in a system like yours, with the 1 inch cubes. I thought that 1 inch cubes might be kind of a small hole for the neck of the plant, though I would guess it would depend on the type you are growing. There are hundreds of variety's of lettuce.

[Luches]

Between the cup and the plug a morsel may drop

[smurf]

Does any one know how close you can plant lettuce together in a water culture system? I am thinking of using this system to grow lettuce just because its ez for them and me.