Temperature at the tops

I have read to keep your HID about a ft from the tops of your plants.What is the normal temp at this range at the top of the plant.What if your HID gives off to much heat and the plants wilt?Is this a normal problem?Do different lamps give off different heat temps?Say like a 400wat HPS?Do different brands give off extreme differences in heat temps?

 

You put a 1k light a foot above a plant without an enclosed air cooled light and you'll burn it to a crisp.
Before you buy a HID light, put in ventilation first.
You'll need an intake and exhaust for temp control and fresh air.

When you get everything set-up, raise the light up high and place your hand right above the planttops. Then lower the light until the back of your hand becomes hot. That's the ideal height.