Can I water when lights are off?

I hope someone can help me as this is my first grow, day 1 of flowering. Is it ok to run my irrigation cycle during the plants dark period? I am growing in a closet, and to get it dark I had to shut the door...there is no air flow, but there is a pretty decent crack as the door does not fit perfectly with the framing, is this enough ventilation? Help.

Clam

its best to feed your plant right before you turn your lights off and for ventilation just have your door open when the lights are on and you will be fine