Heat Issues in my grow tent

darklordmelkor · Apr 20, 2022

Hello all. New grower here.

I have 150x150x200 (cm) grow tent with 1000w HPS running in it. As you know HPS running so hot. It's even hitting 38C right now and we are in April. At Jun, July and August just add +15C or even +20C.

I bought cool tube. My exhaust fan is 580 m3 but it's really didn't change anything. Intake fan is 180 m3 but air inside the room (where grow tent located) is hot. So it doesn't make any difference. Also have 8 inch fan inside the grow room which is running 24/7 but it's still hitting 38C. Also these fans are drying air inside grow tent and lower my RH. I have 5LT humidifier which can evaporate 380mL water per hour.

I don't have any idea. Just looking for Swamp Cooler with huge water and ice container (10LT water container with 2 ice container). Do you guys think it would work at summer peak?

My light is off now and with all fans are on, grow tent is 25C now.

Any ideas except using air conditioner? Because AC and light and other things sucking electricity like a crazy. I can't afford AC now. Any other ideas?

ComfortablyNumb · Apr 20, 2022

We have the same issue in Hawaii. We keep the tent open during lights on with extra fans moving air around them.
Use a no-touch thermometer to check the leaf temps. That is your important temp, not the air.

darklordmelkor · Apr 20, 2022

ComfortablyNumb said:
We have the same issue in Hawaii. We keep the tent open during lights on with extra fans moving air around them.
Use a no-touch thermometer to check the leaf temps. That is your important temp, not the air.

I put probe next to lower branches and it shows 38C when light running on. It goes down to 32-35C when i open tent. Distance is between plants and light is like 50-60cm. Like i said, we are in April now. It will be more terrible at summer peak. Also leaving tent open destroys RH more. It goes down to 25-30%.

Shaded_One · Apr 20, 2022

Switch to LED

(and run your lights during the coldest time of the day)

ComfortablyNumb · Apr 20, 2022

darklordmelkor said:
I put probe next to lower branches and it shows 38C when light running on. It goes down to 32-35C when i open tent. Distance is between plants and light is like 50-60cm. Like i said, we are in April now. It will be more terrible at summer peak. Also leaving tent open destroys RH more. It goes down to 25-30%.

In high heat, you want less humidity to help prevent mold.

ComfortablyNumb · Apr 20, 2022

VPD chart. This gives you the temp range for the humidity levels. Use leaf temp, not air temp.

VPD Chart (Vapor Pressure Deficit) - Perfect Grower Knowledge Database

VPD Chart (Vapor Pressure Deficit) by Perfect Grower

www.perfectgrower.com

darklordmelkor · Apr 20, 2022

ComfortablyNumb said:
ComfortablyNumb said:

VPD chart. This gives you the temp range for the humidity levels. Use leaf temp, not air temp.

VPD Chart (Vapor Pressure Deficit) - Perfect Grower Knowledge Database

VPD Chart (Vapor Pressure Deficit) by Perfect Grower

www.perfectgrower.com

Click to expand...

Thanks for chart. I can keep it around 30C now with damn extra fans etc but i am worried about what's coming at summer peak days. My current 9th week auto's leaves are wilting/curling down because of that heat stress. I can't imagine when room temperature which is grow tent located hits to 35C inside, then grow tent will be like 45-50C.

Have you guys ever used swamp coolers? Do they worth?

ComfortablyNumb · Apr 20, 2022

When we do autos, they are done in 3 months. They have a very speedy life cycle. You may already be getting close. Lets have some pix. When did you plant them?

darklordmelkor · Apr 24, 2022

ComfortablyNumb said:
When we do autos, they are done in 3 months. They have a very speedy life cycle. You may already be getting close. Lets have some pix. When did you plant them?

Here is my thread with pictures.

Why my plants are always small

Hello. This is my first grow and i failed with my two girls. They are pretty small and still waiting to harvest. Then i did put some seeds to soil again and start over. Still, they look so small to me. This two pictures is Autopilot XXL which at day 19 from breaking soil. And this two...

www.thcfarmer.com

Swayz · Apr 24, 2022

Do you have an adjustable ballast? Dropping down to 600w would be ideal for your size and with the autos you won’t need to worry about anybody getting to big and shading the others out.

You could also look into doing the gaslight lighting schedule which would give you some dark periods during the day and help with the heat.

Good luck

ComfortablyNumb · Apr 24, 2022

Looking at the other thread, I see that you were never taught the correct watering method. We have a few here that work, but this one is sure to get you on the right track.

Basic Watering

Marijuana Watering, how media, pot size/shape and environment affect it

Discuss different watering methods for growing your own weed from seeds. Our community members give helpful tips on how pot size and material, as well as environmental factors affect growing cannabis.

www.thcfarmer.com

Watering SOIL

New Simplified Way to Water Marijuana Plants

To know if you need to water your cannabis plant get yourself a soil meter. Poke or drill 4 holes in your pot 1/4 way up from the bottom spaced around the pot...

www.thcfarmer.com

N1ghtL1ght · Apr 24, 2022

Rule of thumb usually you want your air outtake fan to pump the same amount of m3/h as ur lamps watts, so it's way too little. Then vent out of that room with as little curves in the pipe to not diminish air flow. If you take air in from the room, a fan in isnt even requires, just open about 200% in diameter of tent openings as your outlet is.

Then, u r using too much light, that 1000w is for flower, if you can veg under a 400w metal-halide. When plants are still smallish, just arrange them together and put the lamp a bit closer.

Ponky · Apr 24, 2022

My 4' x 8' grow tent with 2 x 1000 watt lights has to be left open with the lights on. Switched to 600 watt bulbs. Can keep closed. Temps stay good. Yield stays basically the same.

darklordmelkor · Apr 25, 2022

ComfortablyNumb said:
Looking at the other thread, I see that you were never taught the correct watering method. We have a few here that work, but this one is sure to get you on the right track.

Basic Watering

Marijuana Watering, how media, pot size/shape and environment affect it

Discuss different watering methods for growing your own weed from seeds. Our community members give helpful tips on how pot size and material, as well as environmental factors affect growing cannabis.

www.thcfarmer.com

Watering SOIL

New Simplified Way to Water Marijuana Plants

To know if you need to water your cannabis plant get yourself a soil meter. Poke or drill 4 holes in your pot 1/4 way up from the bottom spaced around the pot...

www.thcfarmer.com

I did check your post. I will do that. Now i put my fingers through soil like 15cm down and it's pretty moist there. I ordered water meter so waiting for it.

N1ghtL1ght said:
Rule of thumb usually you want your air outtake fan to pump the same amount of m3/h as ur lamps watts, so it's way too little. Then vent out of that room with as little curves in the pipe to not diminish air flow. If you take air in from the room, a fan in isnt even requires, just open about 200% in diameter of tent openings as your outlet is.

Then, u r using too much light, that 1000w is for flower, if you can veg under a 400w metal-halide. When plants are still smallish, just arrange them together and put the lamp a bit closer.

Moving air outside of window works good right now but it's over 40C outside at summer peak. So there is nothing to do about heat issues i think. I need to pump cold air to room for intake fan but there is no cool air. So it will be always hot. I am looking to grow them in hot conditions. I really gave up on heat lol.

Swayz said:
Do you have an adjustable ballast? Dropping down to 600w would be ideal for your size and with the autos you won’t need to worry about anybody getting to big and shading the others out.

You could also look into doing the gaslight lighting schedule which would give you some dark periods during the day and help with the heat.

Good luck

My ballast is not dimmable. I will switch to led but after that grow.

Ponky said:
My 4' x 8' grow tent with 2 x 1000 watt lights has to be left open with the lights on. Switched to 600 watt bulbs. Can keep closed. Temps stay good. Yield stays basically the same.

Yeah. I wanted bigger yields so that's why i went for 1000w. But i see that it was a mistake.

Ponky · Apr 25, 2022

I was lucky and have those dimmable ballasts. Just had to swap bulbs. I think 1000 Watters are better for a 6x6 area at least.

Heath61 · Jul 17, 2022

darklordmelkor said:
Hello all. New grower here.

I have 150x150x200 (cm) grow tent with 1000w HPS running in it. As you know HPS running so hot. It's even hitting 38C right now and we are in April. At Jun, July and August just add +15C or even +20C.

I bought cool tube. My exhaust fan is 580 m3 but it's really didn't change anything. Intake fan is 180 m3 but air inside the room (where grow tent located) is hot. So it doesn't make any difference. Also have 8 inch fan inside the grow room which is running 24/7 but it's still hitting 38C. Also these fans are drying air inside grow tent and lower my RH. I have 5LT humidifier which can evaporate 380mL water per hour.

I don't have any idea. Just looking for Swamp Cooler with huge water and ice container (10LT water container with 2 ice container). Do you guys think it would work at summer peak?

My light is off now and with all fans are on, grow tent is 25C now.

Any ideas except using air conditioner? Because AC and light and other things sucking electricity like a crazy. I can't afford AC now. Any other ideas?

check your water temp if you are DWC. Increase air circulation and use daytime as the dark time for your plant. Too much heat is not good for long period. Airflow and dimmer for light will fix your problem might invest in a cool breeze small device in front of air supply intake

Heat Issues in my grow tent

Heat Issues in my grow tent

darklordmelkor

ComfortablyNumb

darklordmelkor

Shaded_One

ComfortablyNumb

ComfortablyNumb

darklordmelkor

ComfortablyNumb

darklordmelkor

Swayz

ComfortablyNumb

N1ghtL1ght

Ponky

darklordmelkor

Ponky

Heath61

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