Mantis said:
Is there any way you can draw warm air from the house down into your grow? Look for a laundry chute or something similar. If so, I'd think that a well insulated box could hold enough heat through the night. Of course, you won't know for sure until you go through the trouble of building it first.
Rolln J said:
I use an electric oil filled radiating heater to keep the grow room warm after lights out.
PistilPete said:
You could also look into a radiant heat type of flooring down there......A couple of pallets on the floor with hot water pumped through hoses could help ya out.
Wow!
I think all ya'll are making this way - and I mean
way more complicated that this problem needs to be, particularly given that he's looking at a 7x7 grow space.
What I do - and anyone above please tell me why it needs to be more complicated than this - is get one of the nicer space heaters - not a heating element/reflector - something unforeseen and foliage comes in contact you'll get a fire instantly - but a fan w/ a heating coil and a temp sensor buried in a plastic case - and set it to 70. It'll never go off during the day when the HID lights come on (and if it does, bravo to your heat mangement skill), and it'll probably run most of the time at night. Use electrical tape to cover over whatever indicator lights it might have.
If I'm really on a budget, or working inside a very small sapce, get a timer and a $20 heater that you can leave set to "low" and rig the timer to go off for 15 minutes every 30/45 minutes or so.
Space appropriately from foilage.
Another cheapo fix is available from more traditional garden stores, you can get a heater wire to run through your planters to keep the roots warm - again, time appropriately.
Also, Dazed, you'll find the heat that comes off the HID lighting will not only be enough to warm the basement, but over the course of a day's growing, overheat it, 30 degrees outside or not. You need to plan for serious ventilation.
Temperature management is invariably a serious challenge with anything but the smallest of grows.
You also don't have nearly enough wattage - a 7x7 grow space is pretty substantial - 49sqf, but at that level you're down at just over 20w/sqf with a 1000w HPS.
You need to, at least, double that. I'd, and lotsa growers here, would probably triple that.
Go for
at least two 1000w HPS's for that growspace, and choose large, high quality reflectors.