are you using soil or hydro? what kind of water? Any Nutes? How about PH? What kind of light? Temperature? all these questions will help to give us a better idea.
im useing the soil from my pot that i grow in outside i havent added any nutes im useing a 4 foot shop light i dont know about ph and water is rain water that i use for my other palnts the grow room temp 73 all the time