If they are clones they are the same age as the mother. Whatever you feed the mother is good for clones (once roots are established). Growing in soil mix, seedlings don't really need nutes. If I am growing from seed and plan on taking clones, I don't feed the seeding until after I take cuttings, (clones are best taken from a nitrogen deficient mother). After cuttings are taken I feed mother 1/2 strength for 1 feeding and going up from there. Before I take the next cuttings I cut the mom off from FF Grow Big for at least a week or 2 before next clones. Those 2nd clones can take full strength nutes right off the bat. At least that is what I do and it all seems to work.