Lettuce

[Michael sanders]

I have some lettuce that I put on a floating device. The other plants in the grow beds are doing fine but the lettuce is not. Do I need to do anything different for veggies that float?

[TCLynx]

What is your system overall? A gravel bed system and the plants in the media bed are fine but the lettuce in the raft are not?

Since plants in a raft are getting lots more water and don't get the flood and drain, the water needs to have plenty of dissolved oxygen in it. Extra aeration is often beneficial for rafts.

Are the plants in the raft getting as much sun and air flow as the ones in the gravel beds?

[Chris Smith]

What do the roots look like? The health of the plant begins with the roots. In a raft situation it is easy to monitor the roots. Low DO and slimy roots are two common problems.

[Sahib Punjabi]

I also had experienced the same results...further research pointed to two reasons why:

o planted far too early as weather was not favorable for lettuce (that was an easy fix...silly me), and

o the two inch "Net Pots" (now "Slit Pots"), were not touching the water (2 inch raft), and there were no roots extending into the water. I had not given my lettuce seedlings time to develop any roots that extended below the pots.

Once fixed, great lettuce. I was never a big lettuce fan but after having tasted what has grown in the Aquaponics research fish farm (the the salad my wife prepared for me), I have got the "bug"

Good luck...


e

Chris Smith said:

What do the roots look like? The health of the plant begins with the roots. In a raft situation it is easy to monitor the roots. Low DO and slimy roots are two common problems.

[Michael sanders]

I see you are using nft. How often do you clean the pipes. How many gallon a minute is the flow in the nft? I have 4 eight ft and know nothing about nft






Sahib Punjabi said:

I also had experienced the same results...further research pointed to two reasons why:

o planted far too early as weather was not favorable for lettuce (that was an easy fix...silly me), and

o the two inch "Net Pots" (now "Slit Pots"), were not touching the water (2 inch raft), and there were no roots extending into the water. I had not given my lettuce seedlings time to develop any roots that extended below the pots.

Once fixed, great lettuce. I was never a big lettuce fan but after having tasted what has grown in the Aquaponics research fish farm (the the salad my wife prepared for me), I have got the "bug"

Good luck...


e

Chris Smith said:

What do the roots look like? The health of the plant begins with the roots. In a raft situation it is easy to monitor the roots. Low DO and slimy roots are two common problems.

[Michael sanders]

Just trying something different. My system is flood and drain. I have plenty of o2 but not a lot of sun. I am growing in my basement.




TCLynx said:

What is your system overall? A gravel bed system and the plants in the media bed are fine but the lettuce in the raft are not?

Since plants in a raft are getting lots more water and don't get the flood and drain, the water needs to have plenty of dissolved oxygen in it. Extra aeration is often beneficial for rafts.

Are the plants in the raft getting as much sun and air flow as the ones in the gravel beds?

[TCLynx]

Back when I had been doing hydroponics indoors. I would put a T5 4 lamp florescent fixture about an inch from touching the plants only worked well with all the plants about the same height.) I would move the fixture up as the plants grew until harvest. I grew some great salads that way while we lived in a little apartment.

[Michael sanders]

Wow that close I have t5 but not that close they are 3ft from the plants




TCLynx said:

Back when I had been doing hydroponics indoors. I would put a T5 4 lamp florescent fixture about an inch from touching the plants only worked well with all the plants about the same height.) I would move the fixture up as the plants grew until harvest. I grew some great salads that way while we lived in a little apartment.

[Calvin Schmidt]

when growing under lights(especially fluorescent tubes) the basic rule is to get the lights as close to the plants as possible without incurring heat damage. Since fluoro tubes hardly give off any heat you can put them within an inch without any really worry. If you were to use an HPS or HID the light has to be further because of the heat, but those lights put out a LOT more intensity, which tends to work in their favor for larger spaces. Oh and just get the cool white or Daylite bulbs, don't waste your money on "Grow Tubes". I grew a mixture of lettuce, beans, peas, beets, and radishes last winter under a total of 8 T8 bulbs(two shelves of 4).

The big problem with fluorescent tubes is that their light intensity is only really high right around the tube. At one foot distance you lose more than half the intensity, and it gets worse as you get farther.

if the tubes are the only source of light another thing you can do to help is get some styrofoam or backerboard, really anything that is flat white and prop them up along the sides of the grow bed for makeshift reflectors to contain the light. Unless you want to get into mylar reflectors just use anything that is flat white(or that you can paint flat white).

[TCLynx]

Cheap source of reflective mylar are those camping emergency blankets. Far less costly than the stuff you get at the Hydro shop. I actually made a sort of curtain out of one so that the grow lights in the living room were not totally flooding the room with light. Was kinda cool, like looking at the plants through tinted windows yet easy enough to pull aside to tend the plants.

[Paul Letby]

That's a wonderful idea TCLynx! I was wondering how I was going to do just this, and here you are with the answer. Emergency blankets here I come!

I have my raft system under a four foot shop fixture in my light stand. Two T12 bulbs there, and the lettuce gets right up against them with no damage. Here's a pic.

You can see the seedlings are at a disadvantage as they're far from the lights. Not much I can do about that. The reflective curtains will help them out.

[Sahib Punjabi]

Hello Michael,

Just installed them...48ft long. Flow rate is approx 2 gpm...I know I should aim for 3gpm according to some who use such. Let's see...after all, this is my "research" facility :-)



Michael sanders said:

I see you are using nft. How often do you clean the pipes. How many gallon a minute is the flow in the nft? I have 4 eight ft and know nothing about nft






Sahib Punjabi said:

I also had experienced the same results...further research pointed to two reasons why:

o planted far too early as weather was not favorable for lettuce (that was an easy fix...silly me), and

o the two inch "Net Pots" (now "Slit Pots"), were not touching the water (2 inch raft), and there were no roots extending into the water. I had not given my lettuce seedlings time to develop any roots that extended below the pots.

Once fixed, great lettuce. I was never a big lettuce fan but after having tasted what has grown in the Aquaponics research fish farm (the the salad my wife prepared for me), I have got the "bug"

Good luck...


e

Chris Smith said:

What do the roots look like? The health of the plant begins with the roots. In a raft situation it is easy to monitor the roots. Low DO and slimy roots are two common problems.