I have 5 plants in my 1 in. gully right now. The weather was been cold and we had over 8 in. of rain at the house. The butter lettuce is hanging on a growing just a bit. I'll try to put some images up but they are pretty pathetic for the time being. I am in So Cal and all of my hydro is outside.
The lettuce I bought from the nursery, rinsed off the soil as best I could is doing well in the
aeroponic unit. In the future I will stick with this technique in the late fall and winter. I think the NFT lettuce will excel when the weather warms.
On an interesting note, I harvest my lettuce but don't chop off the head to low, (butter and romaine), and then get a complete second head very quickly since the root structure is already there.