wher do you put themometer in tent for accurate reading??

[goldenbrown]

Hello this is my third grow in dr240w tent im using 3x600 hps with diamond reflectors 8inch extraction into carbon filter and 6inch intake fan taking cool air from outside and 1 passive intake from vent also using 2 6inch clip on fans circulating air..My question is when i put my digi thermometer at the base of the plant in slight shade the reading is between 78 and 81 which is about right but when i place it at canopy level the reading is 99f about 37c which i find hard to believe because for sure my plants wouldnt survive 8 weeks of that let alone i pulled near 4zips aplant on my last 2 wid similar temps?? Its just that i read so many posts saying put the thermometer at canopy level for accurate reading... maybe the problem with canopy reading in my tent is that i have a lot of light in ther and everywher is getting hit with a ton of light? Any suggestions on this as it does worry me that im not maximising my yield and maybe less light would increase my yield in this case or putting the thermometer at conopy level is bull

 

[Green Dave]

GB
Put it at the bud level or top of the canopy this is where the temp is important

 

[grobofotwanky]

I have my digital temp sensor tied to a bamboo stake so I can just stick it in one of my container. Its best to take your temp reading at canopy level.

 

[goldenbrown]

Yes but is your thermometer receiving direct light like mine?

 

[grobofotwanky]

Yes, right in direct light. Even with the highest bud, somewhere in the center of the canopy.

 

[goldenbrown]

Well if i put it ther its hitting 100 f!! and plants are green healthy and seem to be doing fine ?????????????? so i will just carry on as i am thanx

 

[grobofotwanky]

Putting your thermometer in the shade doesn't bring down the temp of your growroom. It just makes you feel better about it.

 

[goldenbrown]

You know that ha ha.....but what signs would the plant show if temps are too high??? mine are 4 weeks into flower

 

[grobofotwanky]

http://www.google.com/search?hl=en&q=heat stress marijuana&bav=on.2,or.r_gc.r_pw.&um=1&biw=1366&bih=580&ie=UTF-8&sa=N&tab=iw

 

[mihjaro]

using 2 6inch clip on fans circulating air..My question is when i put my digi thermometer at the base of the plant in slight shade the reading is between 78 and 81 which is about right but when i place it at canopy level the reading is 99f about 37c

Are your clip on fans blowing across the canopy? I don't know how tall your plants are now but 78 to 99 seems a large differential which, to me, suggests that your air circulation is not sufficient or not effective.

The air directly under the lights is going to heat up the fastest so you want to replace that air with cooler air and move that air from under the canopy so it can be exhausted. Maybe, if you aren't already, you can try having the clip on fans setup vertically just below the bottom and as close as possible to the reflector. This should clear out the hot air just above the canopy.

A second thermometer can be used to gauge the differential of the "ambient" air and the canopy air. Minimization of this differential is one of the goals of circulation.

 

[goldenbrown]

Thanx for that it really makes sense what your saying and im going to add 10inch fan to the set up and have it blowing across the bulbs as well as the 2 6inch fans..do u think if i raise my intake air to blow into the fan would help or should i still leave that on the floor?? my intake is bringin in cool air from outside

 

[mihjaro]

Thanx for that it really makes sense what your saying and im going to add 10inch fan to the set up and have it blowing across the bulbs as well as the 2 6inch fans..do u think if i raise my intake air to blow into the fan would help or should i still leave that on the floor?? my intake is bringin in cool air from outside

I'd try moving the 6 inch fans first and get a second minmax thermometer so you can see how it's working. I've seen very good results from just a 6" fan blowing between the plants and the glass. If possible, blow the air towards the filter as well.

Diamond reflectors aren't air coolable are they? If not, then here's a hint for next time you spend any money on your tent: Get air-cooled reflectors, heat shields and a centrifugal fan for an enclosed air cooling loop for your bulbs. 1800 watts is alot of BTUs to unleash in 200 cu ft. It can be so much easier to cool the area under the lights when 50% of that heat is constantly removed.

 

[Gartner]

Its better if you hang the thermometer near the plant some 20cm distance, noting to worry about ,
all is you have to maintain a temperature below 20 degree centigrade..