Plus if you have it to low in the cups the top will stagnate and start giving you all types of problems. Just do like mentioned above and only leave about 1" from the top with no soil. Also remember not to feed any nutes until at least the 4th to 5th nodes as a lot of n00bs believing you can give your plants 100-100-100 <~~~(exaggeration) NPK ratio and they will grow massive. :wtf: LoL you'll kill those suckers for sure. That was like my buddy asking me if he had to put the male and female together to make it bud! LoL I just snickered and thought to myself, "that was me at one time."