so i got my new seeds, germinated them, and i got little plants coming out from the pots, like 2 cm tall, but my only light is a 400w sunmaster HPS, should i put them under that light, or i need another light?
i would wait to put them under that 400 till they get bigger, if you don't have another light make sure you keep that 400 far enough away from your plants so they don't get burnt up.
It should be just fine. But as thugnutz sez, keep the light about a meter or slightly less above the tiny seedlings. Recall that cannabis sprouts that have just popped above the soil outdoors can immediately handle full sunlight intensity. Even when they're in full bloom keep that 400 HPS at least half a meter or more above the tops.