Typically you don't want to feed any nutrients untill at least 3-4 weeks old, depending on your medium. If you're using soil, that can vary depending on the type of soil and what may or may not already be in it. If you're doing hydro, I can't say because I'm a soil guy. Others may be able to help in that area. I look at adding nutes like raising a human baby, you don't give a newborn a steak and expect it to be able to handle it, it needs mushed carrots and peas and all that stuff first before it can handle "real" food. I usually wait until the plant is about a month old, or 10-14 inches tall before I add any nutes.