Lightless Heat(er) during lights out

Needing to regulate temps at night and I'm looking for a heat source that emits no light or red glow. The closet is small, so the space is easy to keep warm.

It doesnt seem like my little heater from honeywell puts out enough red glow for it to affect the flowering, but i maybe wrong. If you think about it the moon is probably brighter than that.

I found a heater that doesn't golw but it has a small red light that duct tape covered. I asked to turn on the heater to see before I got it.

A small oil heater. Radiant heat is better then forced heat.

Thanks for the responses. Radiant heat is probably the best, but my closet is small, so fitting one of those stand up models in there would be a challenge. I am using a little heater that seems to give little, if no red light, when on the low setting. Like Match Box said, I just put tape over the little light that comes on when the unit fires up.