That depends on if yer starting from seed or clone, in soil or hydro. I grow hydro and don't feed seedlings until I see growth taking off and the cotylodons yellowing off, and then it is real mild nutes like 1/4 strength. For clones I don't feed until I have roots enough to set them in permenant homes, then I go with 1/4 strength nutes again to get started. While they are in the cloner, I spray them daily with a mixture of vitamin solution and ph'd water. seedlings I don't spray. I start all my plants on 1/4 strength nutes then increase it to half after about a week. Then increase it again to 3/4 strength after another week or two depending on what the plants tell me. Hope this helps bro. green mojo