You can use it any time you want, but they won't use much CO2 until they get over 1' tall, and even more during flowering.When should i use dry ice and how much should i use in a 6'x2' closet?
Should it be used during light or dark hours?
if you dont mind me asking....how do you know? C02 from airsoft gun is NOT going to get you in the PPM's you need to be in to make any differenceAnyone play airsoft? I busted a co2 for a airsoft gun in my closet once a month, and they love it!!