No body knows at lowes or Home Depot what kind of thermostat I need. There is a Honeywell Winter Watchman that turns a light on in house if temp drops below a setting, but package doesn't say if turns off when temp rises. What is everyone using, and where can I find one?

What you need is commonly called a "greenhouse thermostat",
Such as these sold at Amazon:

http://www.amazon.com/s/?ie=UTF8&keywords=greenhouse+thermostat&tag=googhydr-20&index=aps&hvadid=44767593825&hvpos=1t2&hvexid=&hvnetw=g&hvrand=162400822488771206&hvpone=&hvptwo=&hvqmt=e&hvdev=c&ref=pd_sl_1hmxiuf0s3_e

(I have the fourth one down in the list)

A few years back I bought an HVAC thermostat at Home Depot (used to control auxiliary fans,etc. in HVAC systems. That was the closest thing I could find there, and it more or less worked, but it was not calibrated for labeled for the temperatures (just a knob labeled from Cold to Hot)

My greenhouse thermostat lets me set it to the exact temperature I want it to activate at. Upon warming up, the output turns off a few degrees above the turn on point.

Great! Thanks for the link. I found the "Thermo Cube" today at a local Tractor Supply and got 6 of them. It is just a plug with two 3-prong electrical sockets so you can link to another lamp/ heater and run two on one plug. The Thermo cube plug allows your device to come on when temp gets to 35• and cuts off at 45•. I hope it works. Easy to hook up.

Thermo cubes are working!