Hey...could be not having your lights close enough....I'm no expert but I made that mistake on my last grow for the first few weeks. What lights are you using and how close are they?
@MissSolasolita, I have 2 26w CFL's with 1300 lumens each, and i've allways been carefull to place them no further than 4 cm from the plant. I don't think that is an issue but i do got tons of other issues that caused this mini plant. My maria is about to go into flowring hahaha