if your problem is heat try the green house effect , Just cover your plants with a see through plastic paper ( careful not to break any thing lolz) but this method also creates a lot of humidity and may dry ur plant but if your temps are that low it would help. not a lot of lights could compare with the sun, not even on an over cast day ( KEY WORD NOT A LOT may be some dude got some200,000 watt mh or some shit u never know)