I am going to give a 4x4 a go right now for my first attempt. See what the power bill does. I only need about 4 oz a month to keep my back from going into spasm.
I am just north of Edmonton.
Do you think a 1000 in a 4x4 would be good ?
Or a led perhaps?
I am definitely going to heat the garage up quite a bit before I open the flaps. But I am afraid of when the lights are off it will be too cold.
A 1000W will be great in the winter but for a ground level grow I'd lean toward a good COB LED system but you won't be getting all you need plus a decent LED for 500. I have about 4G invested overall but that's spread out over almost 20 years.
You're going to want to have a heater on a thermostat in the tent for their night time unless you want to keep the garage heated all winter and that won't be cheap. You'll also want to wrap the tent in blankets or something to insulate it or the heater, if you can find room for it, will be going all night.
You'll also need a good circulation fan in there as well. Oscillating fans work best so you're not blasting the plants with a steady stream of air. Or a wall mount type fan that could be hung upside down or mounted off the floor so it's out of the way.
Power ain't cheap for sure and mine works out to 23.5¢/kwh so damn near $90/mth to run 1000W light 12hrs/day for a month. Not so bad when you can pull a couple pounds from a harvest tho. That's the most expensive part of my growing and I use those rich man's AN nutes! Makes me laugh when haters bitch about the high price of bottled nutes. $200 worth lasts me 5 years so is nothing really compared to the power needed to use them up.
My basement is pretty cool all year round and all the air for my grow room comes from the basement area thru filters so have never needed A/C. You'll probably want to time your growing so you are just vegging smaller plants during the summer under a smaller light system of some kind or you'll be needing AC for sure.
If you insulate the tent for winter a small 500W heater will be good enough. I have a 1500W one and only 750 of it switched on and it's more than enough to keep my room that's 7x9' warm enough. I got a baseboard heater thermostat wired up with cords to switch the heater on and off as needed. It can get down to around 35F in the basement come Feb when the cold winds blow. Never gets over 63 or so all summer. 61 now.