Dry hydroponic

This nursery grow lettuce in  pools and in the ground, in the pools they use a dry hydroponic system, so when you harvest you may have a couple dead foliage but not rotting to the lettuce. For the pool lettuce , the lettuce sit in a float which is in water. Summer growing is 3 times better than winter, in winter they need to keep the water warm.
The lettuce gets put in the float at one end, then as you harvest the opposite end, the float moves down the pool. They sell different markets, at the moment the lettuce is selling 26 cents euro ,but should  be 35 cents euro.