simple temperature question

is 79 to hot to grow light is 22 inchs from my temp. sensor.trying to get things right before i put my plants in so basicly the light will be 22 inchs from tops of plants and the temp will be 79 degrees will this be ok the reflector is air cooled but just have 1 165cfm fan cooling the light and a 425cfm inline fan and filter in a 4x4x6` growbox.any responce would be appreciated...

your girls will love 79 degrees

FYI - you measure air temp with thermometer shaded from direct light, so your temps are probably actually lower than 79

thanks for the quick replies all...so i shouldnt measure the temp under my light,i should measure the temp of the whole growbox not directly under light is that right sorry i`am alittle confused about what is the right way to measure the air temp in my growbox.

try writing down the temp from a couple different spots of the grow area and see what you average, then see what itll take for you to drop your temp more if you want. or where to point a fan or so such. But 79 is pretty good. Just its always gonna be hotter at top of course.

22inch from the canopy? What light is that??

its a 600 watt mh/hps

Reason I ask I because I would think being 22inch away would make those babies stretch. Im no king dick but I sit my 400w about 12 maybe 13 inch

tinagrowgood said:

thanks for the quick replies all...so i shouldnt measure the temp under my light,i should measure the temp of the whole growbox not directly under light is that right sorry i`am alittle confused about what is the right way to measure the air temp in my growbox.

Click to expand...

You want the thermometer Under the light at the top of the plant canopy, but shaded from direct light. If you let the light hit the thermometer you will be measuring the combination of radiant heat and air temp, and the air temperature guidelines are for air temp only. To get the right radiant heat you place your hand at the top of the plant canopy and lower the light as far as you can with your hand remaining comfortable, but no closer than about 12 inches or you'll be giving your plant too much light.

In a grow box with your 400w HPS/MH? (theres no 1 bulb of both) MH burn (blu spect) warmer then HPS(red spect). With an air cooled hood the temp from the bulb is pretty much taken care of. Dont worry about "spots" where its warmer, its always going to be warmer near the tops of the plants cuz of the light. VENTILATION and EXHAUST is the answer to your question, just keep the temp approx. 75-82 (exactly where depends on the strain). Just keep the air moving in, thru, and out. (note* if your using CO2, stop ventilation at those times or just hook it up to your fan)
Sounds like you have it tho. You dont need to trip if you have two fans in a 4x4x6 box

well guys and girls i think i have got it down and under control.did as told i shaded my temp sensor from the direct light and placed it about 16 inchs from top of canopy so that i wouldnt get a combination of radiant heat and air temp.well its 77 to 78 and then i placed me temp sensor up high so that it would give temp from the top of the growbox and it hit 80 but thats where all the hot air rises so i think its all good now at least i hope,only one way to find out thanks everyone for all your help....you guys and girls rock!!!