can you plug heating and cooling equpt. into a thermostat simultaneously?

I need my thermostat to activate my fans during the lights on cycle and my heater during lights off. My max/min fluxuation is way too high. Nights are too cold, days are too hot... Do I need 2 thermostats or can I make one thermostat activate either my fans or my heater depending on the temperature? Thanks guys! I really dont want 2 thermostats...

heres the thermostat Im going to get.
I might just get a space heater with a built in thermostat ($60) to sit in the room but outside of the grow box, set the temp of the heater to the lights off temp so the temp doesnt drop below that and then hook my fans up to my grow room thermostat to control the lights on temp. The heater would be activated when temps are too low and the fans are activated when temps are too high; idiot-proof. Thats gotta work right? Is there a better way to do it though?
http://cgi.ebay.ca/Digital-Cooling-Thermostat-Temp-Dne-/110525504398?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item19bbd55b8e

nm, just gonna keep my room temps under 72F and hook that thermostat up to a heater and then it will control both day and night with no need for cooling during lights on. Im exchanging the air in my box 5 times per minutes so I shouldnt have heat problems; solved! what a pointless thread...