Anyone using 1000 watt hps? I have one simple question.

I'm trying to figure out which temp means the most. I bought a dual use thermometer. It's for inside/outside temps. It has a wire on it that can be placed outside to read the temps.

I put the thermometer directly under my 1000 watt hps about 2' away from the glass and ran the wire to the side where the direct light don't hit it. The temp reading under the hps is around 100 and the temp reading to the side is around 85.

I'm a bit confused about what temp is the one I should go by. Do you guys go by the temp right under your light? Or the temp off to the side?

The weird thing is that I can hold my hand under the light from about 1' away and it doesn't feel that hot. My hand doesn't get uncomfortable at all. This seems strange. It's a vented hood with gasket enclosed glass.

ps...I used 3 different thermometers and all had the same or very close readings.

Thanks

the reading on the outside is the one you are looking for, you want to get the general air temp in the room. So long as you have fans blowing over and through your plants it will be the room temp they are feeling and not the direct heat from just below the lamp.

regrets said:

the reading on the outside is the one you are looking for, you want to get the general air temp in the room. So long as you have fans blowing over and through your plants it will be the room temp they are feeling and not the direct heat from just below the lamp.

Click to expand...

it is my role in life to follow regrets around and say "what he said" to the other noobies.

anyway, the heat directly under the light is radiant heat like you'd get from a heat lamp or under direct sunlight. the temps that are quoted for weed growing are ambient temps which is the air temp. as regrets said, make sure your air circulation is good,

Thanks to the both of you. Took a load off my mind!!

I believe I can get the ambient temp to around 82/84 at best. I have great air flow but my central A/C can only do so much for ambient temps.

LOL I can probably set my A/C to 72 but it would never turn off.

Thanks again guys

AHHH this helps a lot as I have been having the same problem, underneath my lamp, where my thermometer is is at about 92F but not in direct light it is about 75.

so because my room temp is at 75, thats what I want right? It doesn't matter that under the lamp is 92F?

Take the temp very near the plants *at plant height* above the level of the pots and just outside the throw of the light.

Not out side of the grow room or closet, not lower or higher than the plants, not on a wall that feels cooler or hotter than the air in the room. If need be hang the thermometer in free air, or the probe.