I have a WF that has a column, and a tall reservoir with space for four separate plants on top of it. Take look at this post for details.
I have planted tomatoes, basil, parsley, rucola, coriander, strawberry, chili, and lettuce so far, and I’ve made some observations. Since my design only has one airlift, and the reservoir pot has much more rockwool, than the small pots in the column, the benefits of hydroponics are not as obvious in the reservoir pot. The plants in there are growing ok, but only about as fast as stuff that I grow in traditional methods, in soil.
My conclusion is that the amount of water flowing through the growing medium does matter. It’s not enough that the rockwool is moist all the time, there must be flow. The flow pulls in fresh oxygen for the roots allowing the plant to grow faster. What I’m planning to do is switch the plants in the reservoir pot to herbs and other stuff that I’m not using in such large quantities.