These are starting out so they are in small pots now, correct? If yes, then just wait until they are ready to transplant to bigger pots and get the soil right for the next pots. See link in my signature about importance of re-potting. Assumes you are doing a soil grow.
bigsby Reviewed by bigsby on . why did it go back to 3 leaves? The set-up i have is two plants, with 2 -75 watt flourescent tubes. the 2nd tube was just added, and before that the top had 5 leaves, now that the 2nd light is there, the top is back to 3 leaves. why would this happen? Rating: 5