Just starting out they are 2.5 weeks from sprout growing in a 18x22 cab under 6 24w 6500k cfls. They are in 3x3x4 inch starter pots. Slightly watered them twice and on Saturday gave them water and 1/2 strength Jacks Classic I'm starting to see problems. There is a fading yellow showing up on the tips of the leaves I have attached a picture and can get more..
what he said ^. You don't need nutrients for at least 30 days. Your plants come naturally equipped with nutes. The initial leaf's that sprout are called cotyledons. Once they die and fall off is usually the point when I introduce nutes... Depends on what the plant is telling me though. The leafs are like the face of the plant. If the leafs look good... then she's fine and don't touch it!