temprature

help!!! can you tell me if its ok to have an average temp of 80 to 85 or will they burn up

better to get in the mid 70's but you're ok. make sure you're measuring temps in the shade.

your good but if you get it lower you can get better yields

Anything over 85 and growth slows drastically. Keep them low like other have said. Anything over 90-93 and they will die.

MY closet is at about 30 degree celcius...... or 80F is this cutting it too close ?

eza82 said:

MY closet is at about 30 degree celcius...... or 80F is this cutting it too close ?

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30 is a little hot. 26-27 would be better.

GrnMan said:

Anything over 90-93 and they will die.

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I'm gonna have to raise the BS flag on that one

Some of the best weed in the United States is grown in California and the summer temps there can get well into the 100s.

Don't get me wrong... I'm not saying high heats are ideal for plants.... but there are more factors to it then just a blanket statement that all plants will die if the heat exceeds 93 F.

For example... the poster doesn't say if this is soil or hydro. For hydro I'd agree about the heat.... over 90 and they will likely die unless the res has a cooler in it to keep the water temps in the low 70s.

Soil is a little more forgiving of higher temps as the water going in cools the roots and the moist soil helps keeps them cool and protected from the heat.

Anyway... that's my 2 cents

eza82 said:

MY closet is at about 30 degree celcius...... or 80F is this cutting it too close ?

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if it's steady at 80 degrees and your humidity is in check your good. a little colder would be optimal but where your at is fine and is not going to hurt anything.

depends on humidity, if you have high humidity you are going to have a higher temp, but that high temp is not that same as having a high temp and low humidity, your plants burn faster under DRY HEAT. Also you want humidity during veg only, so during veg if you have high humidity (80-100%) and your temp is pushing 85F you are good, but if you are pushing a constant 85F with 0-30% humidity your plants may burn in a couple days and you will see deficiencies more clearly

80 degrees is fine. Consistency is what matters.

bobbyboy34 said:

depends on humidity, if you have high humidity you are going to have a higher temp, but that high temp is not that same as having a high temp and low humidity, your plants burn faster under DRY HEAT. Also you want humidity during veg only, so during veg if you have high humidity (80-100%) and your temp is pushing 85F you are good, but if you are pushing a constant 85F with 0-30% humidity your plants may burn in a couple days and you will see deficiencies more clearly

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GREAT INFO...... Thanks guys.

Info above was what I was looking for....

For everyone who helped toke on this ............

I agree that 80 is fine. My 6'6" square grow tent has been sitting on 40c all week, thats around 105f.
But it's 38 outside so there's nothing I can do about it, I use cool tubes and an air con inside the tent.
Most of my plants are doing fine so whoever said they will die over 93f is giving out false info.
So what happens if you live in Thailand where it's 36c and high humidity? they still grow some awsome pot there.

spiked1 said:

I agree that 80 is fine. My 6'6" square grow tent has been sitting on 40c all week, thats around 105f.
But it's 38 outside so there's nothing I can do about it, I use cool tubes and an air con inside the tent.
Most of my plants are doing fine so whoever said they will die over 93f is giving out false info.
So what happens if you live in Thailand where it's 36c and high humidity? they still grow some awsome pot there.

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I thought that was a bit strange from GRNMAN... Im australia and rooms here get HHHHHOOOTTTT mid summer...... But wicked buds ! But I can not say I had a thermo with me to measure but they were about 40+ degree celcius...

spiked1 said:

I agree that 80 is fine. My 6'6" square grow tent has been sitting on 40c all week, thats around 105f.
But it's 38 outside so there's nothing I can do about it, I use cool tubes and an air con inside the tent.
Most of my plants are doing fine so whoever said they will die over 93f is giving out false info.
So what happens if you live in Thailand where it's 36c and high humidity? they still grow some awsome pot there.

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well see a lot of things play a part, the ambient room temp may be that high, but im sure you have air blowing from fans, just think about it, during a hot summer day it is going to feel hotter outside when its 100F with no wind, but if its still 100F and there is wind it feels like 5-10 degress cooler

also, weed will still grow but very slowly or even hault growth. This hi heat also raises your res temp, which is bad. Im not disputing your results, its just that the 70-85F ambient temp is for best growth results. GROW ON!!

I'm certainly not disputing the reccommended temps, It's just that in summer here in the sub tropics it is incredibly hot anyway.
I do have a 40cm fan oscillating on my plants with a portable aircon behind it to blow cooled air onto them.
I use cooltubes and my ballasts are outside the tent, but it's still very hot in there.
My 2 gallon pots can dry out in a day so I have to be vigilant with watering.
Actually some plants are struggling and they are 100% sativas, and yesterday one of my plants just up and died for no particular reason. It looked healthy enough and had just started budding. I hate summer here man, but winters are nice.

spiked1 said:

I'm certainly not disputing the reccommended temps, It's just that in summer here in the sub tropics it is incredibly hot anyway.
I do have a 40cm fan oscillating on my plants with a portable aircon behind it to blow cooled air onto them.
I use cooltubes and my ballasts are outside the tent, but it's still very hot in there.
My 2 gallon pots can dry out in a day so I have to be vigilant with watering.
Actually some plants are struggling and they are 100% sativas, and yesterday one of my plants just up and died for no particular reason. It looked healthy enough and had just started budding. I hate summer here man, but winters are nice.

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plants that die all of a sudden is mostly due to res temp, i has beautiful plants die mid bloom because the roots were getting too hot, no o2 in water at high temps, root rot sets in quick...bacvk then i was not even checking res temp, best believe i am now

humidity, fans on plants play a good part

i think i read somewhere that CO2 is helpful in high temps also

When your venturing in the higher temps the problem is not overheating your plants. When your grow room is just a little warmer, around 29-32*+ you hit that sweet spot for mold/mildew reproduction. If you keep your humidity in check the risk goes down.

But keeping your grow room a little cooler, 25-26* and your out of the range for mold/mildew reproduction. And lower temps will slow down infestation of bugs. Also you should be bringing temps down to 18-20* at night ideally.

i thought the risk of mold/mildew/fungi was from keep the soil moist to often?

needhelp said:

i thought the risk of mold/mildew/fungi was from keep the soil moist to often?

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That would be algae. Mold and mildew spores are present in the air, Always, even right now in your house. When the conditions are idea they will settle and reproduce and you need mold spots on walls in bathrooms or toilets, etc.

The powdery white mildew is so common because people overlook simple things like changing the environment to conditions where the mildew cant reproduce, if it cant reproduce then it cant infest your plants.

Grey mold (botryitis) is a little different, high humidity, wet spots, wet leafs sitting on a bud, Wet buds leaning on each other during drying.... things like this can cause grey mold.

Keeping humidity in check, and ideal temps and you wont have problems, also increasing airflow with lots of oscillating fans so the spores cant settle.