I thought you ment harvesting two plants in your grow area every two weeks .
When i,ve done that sort of thing with hydroponics i had to take the fertilised feed from the ones due to come out next and feed em with water by hand .
It,s not realy a bastard , it,s just me being a bit lazy
Yes if all the plants are coming out then yeh obviously you just change your solution to pure water.

But like i said i know very little about airoponics i use a gravety feed hydro drip with censor cones for each plant.
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