Correct Method of Measuring temps in PC growbox

Hi All, just started a new grow with a PC tower growbox I made. I have been reading a lot and have a decent setup with seven 23watt CFLs with lots of exhaust fans (3 x 89mm and 1 x 120mm) towards the top of the box and two intakes at the bottom (they also serve to help circulate air). I read a lot about temperature recommendations but have not come across a good discussion on how to measure the temps. If I place my thermometer on the floor of the grow box, my temps never go higher than about 3-4 degrees above ambient temp (ambient is high 60s to low 70s). If I place the thermometer right under the light, the temperature goes up to low 90s. Now I know that this is partly a result of radiant temperature on the thermometer which does not give an accurate air temperature. Also, if I use a box to prob up my seedlings closer to the light source, and place the thermometer in the shade, the temps are also lower. In summary, I can get wild swings in temperature measurements depending on where (how high) and how (in shade or direct light) I place the thermometer. This leads to two questions: 1) Recommended temps are usually low 70s to low 80s. Does that refer to shade temperature? or measured temperature at the leaves/ buds? (i.e. When we check the weather, and it says 80 deg and sunny, that's shade temp....it may be 100 in the sun). 2) I just started from seed and the plants are about 1/2" tall. I tried to feminize them with banana peel (ethylene) method for whatever that's worth but figure no reason not to try. I know that one of the factors that effect gender outcome is temps. I am trying to figure out whether it is worth lifting the seedling up to the lights where i get temperature measurements of low 90s (and get less stretch and more lumens) or keep them on the ground (where the temps are mid seventees) and increase change of females. They are lifted up right now but I am seriously considering dropping them to the ground because I started with only two seeds and don't want to get assed out with two dude plants. Also, I have a decent amount of CFLs (161 watts crammed in a tiny box), so i probably have enough light for vegging without serious stretch. Once I kick them into flower, I will get them closer to the CFLs. Any thoughts are welcome! I am attaching a pic of the box just in case (its a mid tower with white elastomeric paint). Thanks!

hi, sorry, i think i posted in the wrong section of the forum. i don't know how to delete but will report. thanks

no you just wrote way the fuck to much.

the only temps that patter are where the plants are....if theres no plant in the space it dosent matter if its 120 degrees as long as your plants stay cool

aand writing long posts is never a bad thing. detailed posts help most of us who arent afraid to read a little bit give you better answers...nothing worse than a post

"my plants are dying whats wrong?" and no pics or anything.

Monitor the top of the leaf canopy, thats where it will get the warmest for the plant. aim for a max of 85.

As said above canopy temperature is what you want to measure. You can avoid the radiant heat on the metal probe of the thermometer with some common sense (hint: shade)

Also. Please discover paragraphs bro.

thanks all for you help!

I hear you on the paragraphs. ( i installed some antiscript plugin and it screwed up my ability to use paragraphs...as i discovered later)

As far as the shade, yeah, that part I figured out. I just didn't know which temperature mattered.... If you read people's grow journal's they don't usually address that. Pictures never show the thermometer probe "shaded". So I was wondering if recommendations on proper temperatures were based on temperatures measured by thermometers in direct light.

SnotBoogie said:

As said above canopy temperature is what you want to measure. You can avoid the radiant heat on the metal probe of the thermometer with some common sense (hint: shade)

Also. Please discover paragraphs bro.

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