does your temps fall as your plants grow?

[WarBux79]

Hi,

Currently in my grow box I am unable to maintain temps under 90 F with all the lights on. In order to maintain temperatures under 85 I have to turn off one of my main lights. The whole box uses reflective mylar. My brother grows and said that his temps actually fall the bigger his plants get or the more plants he has in his grow box. Has anyone else noticed this, and if so how much of a difference do you see?

 

[DEAN420]

Well i have noticed a difference in temps when i have more plants in my room but can not be sure for if it was because of the plants .

Once i had 24 plants in a SJ Darkroom 240L but had two different strains on the go, one set finished b4 the others making me have to harvest 12 plants and leaving 12 plants within the tent. When i done this and over the next two weeks i noticed a change in temps between 5 and 10f on the higher side.

 

[Indicana Jones!]

Hi,

When I first did a static test of my grow room with no plants I was hitting 90 degree's. I decided to go for it anyway since I had the setup and I had the seeds. Now 3 nearly 4 weeks along I have noticed my temps are down to the mid 80's, 84, 85, 86 and has been pretty stable at the 84 to 85 range regardless of the outside temps. I can't say for sure it's the plants, but something has taken the temps down and I haven't done anything.

Cheers!

Indicana.

 

[gnome grown]

smke

 

[McBudz]

Are you guys starting off with brand new bulbs? I notice the bulbs become less hot over time (probably put out less lumens too).

Interesting to hear most people see the same sort of thing happening.. I've never noticed my self..

 

[PitViper]

Ive checked my temps all the time and Ive never had any variance. I also change my lamps every 12 months

 

[WarBux79]

I think it has to do with the number of plants changing.

 

[moe323]

could it be that water is being added at the same time as the plants and it's changing the humidity of the room which in turn cools the air temp down? the bigger the plants get the more water they require so higher humidity levels.

 

[Flurple]

i would think the more plant matter the higher the temp, photosynthesis is an ongoing chemical reaction with a byproduct of heat. IMO its probably outside temps or ventilation or your bulb is acting funny

 

[WarBux79]

I am pretty sure the more plants the lower the temps. This is the explanation my brother gave me. Plants want 100% humidity as they get bigger they perspire more. This raises the humidity in the grow area which in turn lowers the temps.

 

[drdanks]

just make sure that you have air moving @ the plant level. 85-90 is ok they flourish in the 75-85 range. cannabis also responds extremely well to a 10+- (difference) in the temp between the night and day light cycles. always water as the lights are coming on. this will also help with the humidity. size of light? light schedule? distance from top of cannopy? anyone else have anything to add?

 

[Flurple]

hmmm i didnt consider the humidity... ill see if that happens in my room as they get bigger

 

[OldSkoool]

As a single plant grower, I'd be unable to make a judgment, or comment regarding plant generated heat, but drdanks comment regarding day/night temp swings did catch my eye.

Using the same logic, I started my current grow later than previous plants normally started in Spring/Summer, to test the difference of larger light/dark temp swings in my grow room, which cools down considerably during Fall/Winter months. I've been able to maintain 65 degree's during dark, and 78 degree's with lights (CFL). This certainly isn't scientific, but after 10 days into flower, I have noticed the buds maturing faster, and are much fuller than previous Spring/Summer grows. While this could be attributed to the strain, emulating a natural outdoor environment certainly can't hurt.

 

[WannaBcntryGy]

It would make sense at least during the vegetative stage,a cool down in the evenings promotes fruit & veg growth. My plants are about 10' from my window and I always leave it cracked & at night I shut my lights down and the apartment cools down. My plants are exploding with hairs....So it doesnt seem to be having a bad effect

 

[Jamahl]

Evaporation = conversion of liquid water into gas or vapour water. This takes energy.

Hence evapotranspiration will cool the room down due to using energy to convert water from liquid to gas.

Add to this the fact that more plants means more leaves converting light energy into carbohydrates rather than the light energy bouncing around until it creates heat in the room.

Thirdly, as already said, increased moisture vapour decreases heat and a air column with a greater humidity requires a greater input of energy to increase the temperature (more thermal mass to warm up).