Put your hand where your plant is.. if your hand can STAND the heat.. then so can the plants

Ideally, a healthy vegging plant will have the HID, 6 inches from the canopy.... Ventilation is key... You want to pull the heat away from the plants.... This is how you get 1 gram per watt.. keeping the lights as close as possible..

your worry is valid... and you should keep a close eye on your plants , burnt plants are depressing...

love

you can always put you pots on a GRATE.. and put a fan under your pots.. The fan will be blowing directly UP through the grate, through your plants.. blowing all heat up and away from your plants...

as long as the room temp is not a problem, this method is FULL PROOF...

COOL tubes are also amazing!!!!!!!

love