OK, I'll bite... another noob question...
The weather here has been shit, pretty cloudy/rainy, about 15c (60f)... so I've been growing seedlings under a 400w HPS to get a head start.
At those temps, on a cloudy day, am I wasting power leaving them under the light? They will eventually go outdoors to veg and flower...
Also, they would be under one of those mini plastic greenhouse-thingys.
Thanks.