High temp issue

[maryjanesdad]

I'm running (5) 600w HPS lights in a 10x 10 room with a 6in inline fan/ filter outtake and 10in passive intake. Room held a steady 72-76 degree temp. Recently with all lights on full capacity I'm hovering at 80-83 degrees. I plan to add an appropriate mini split conditioner when I have some extra funds but for now I need to cool the room this way.

Would switching to an 8in or 10 outtake make a big difference in cooling the room?

What if I added a fan to the passive intake, would that get be a big enough change to keep temp where I need it?

Thanks.

 

[PurplePotion]

I'm running (5) 600w HPS lights in a 10x 10 room with a 6in inline fan/ filter outtake and 10in passive intake. Room held a steady 72-76 degree temp. Recently with all lights on full capacity I'm hovering at 80-83 degrees. I plan to add an appropriate mini split conditioner when I have some extra funds but for now I need to cool the room this way.

Would switching to an 8in or 10 outtake make a big difference in cooling the room?

What if I added a fan to the passive intake, would that get be a big enough change to keep temp where I need it?

Thanks.

Use a bigger/another fan for your exhaust. Make sure the surface area of your passive intake is at least 2x the area of your exhaust. There’s a lot of variables we don’t know so you’re going to have to do some tinkering, but either way it sounds like you’re going to have to buy a bigger fan. You could use the 6” as an active intake or run them both as exhaust... or ditch the 6”.. that’s the part you’re going to have to play with.

 

[Douglas.Curtis]

May not be an issue, but please be sure all lamp cords are tucked up out of the way of the 'light.' Infra-red will heat up black and other dark colored cords quickly, increasing the resistance. This increases the wattage draw on the ballast, which increases temps, while it raises the temp in the cord trying to combat the increased resistance, which creates more resistance and... well you get the idea.

My goal is always 3 complete exchanges of air per minute. It allows air cooling in areas with much higher outside temperatures and a lot of other benefits. Definitely up the flow.

 

[troutman]

Just add another exhaust fan and things should get better. The passive air intake will increase without a fan when you get an extra exhaust fan.

 

[Cmoon]

6in wont hack 3k, im with these guys but do the biggest fan affordable (easier to turn down then up) throw the 6 in on inlet and trial vent openings to get the best conditions.


while your upgrading flip floping the lights will reduce temps but reduce overall illumination but its just an option while you get the fanny in or any sticky times with multiple lamps.


bests cm

 

[maryjanesdad]

while your upgrading flip floping the lights will reduce temps but reduce overall illumination but its just an option while you get the fanny in or any sticky times with multiple lamps.


bests cm

I'm in week 4 at 9am-9pm so I was considering flip flopping their light schedule but was concerned with them having 24 hrs of dark...I didnt think its wise to mess with them...but I'm sure that would solve my temperature problem.

 

[maryjanesdad]

May not be an issue, but please be sure all lamp cords are tucked up out of the way of the 'light.' Infra-red will heat up black and other dark colored cords quickly, increasing the resistance. This increases the wattage draw on the ballast, which increases temps, while it raises the temp in the cord trying to combat the increased resistance, which creates more resistance and... well you get the idea.

My goal is always 3 complete exchanges of air per minute. It allows air cooling in areas with much higher outside temperatures and a lot of other benefits. Definitely up the flow.

I have my cords along the ceiling. Never knew that, good stuff!

 

[PurplePotion]

I'm in week 4 at 9am-9pm so I was considering flip flopping their light schedule but was concerned with them having 24 hrs of dark...I didnt think its wise to mess with them...but I'm sure that would solve my temperature problem.

He means staggering individual lights on and off throughout the 12hr light cycle so that only X number of lights are on at any given time. X being the number of lights you can run and keep the temp where you want it.

I definitely wouldn’t do a full 12hr switch to flip the actual time of day your lights are coming on.. that’s asking for trouble like you said. Definite hindsight is 20/20 situation.. it happens.. now ya know

 

[superpedro]

I'm in week 4 at 9am-9pm so I was considering flip flopping their light schedule but was concerned with them having 24 hrs of dark...I didnt think its wise to mess with them...but I'm sure that would solve my temperature problem.

That will mess with their circadian rhythm. Can cause hermies.

But there may be a way to do it with low stress, in my experience.
When studies have been made of plants and their rhythm, the shift in proteins can be measured keeping the rythm for days in dark. But as it fades the duration between peaks and lows gets longer. Instead of a 24 hour cycle, it becomes a 25-26 hour cycle.
What experiments in SDPs (Short day plants) have also shown, is the ability to grow and flower in a 25 or 26 hour cycle. Like 12½/12½ or 13/13 instead of 12/12. Plant go by comparing duration of darkness to daylight.
I have done that on a few occasions when my work hours have changed, and made it impossible to service my plants.
Havent tried a complete 12 hour flip, but never had issues with shifting 4-6 hours..

 

[f-e]

As hot as 28c, the optimum leaf temperature for cannabis growth?

I wouldn't want to grow at 72-76. I mean.. 72? I just couldn't. That's not even the design temperature for watching TV.

Where are you taking these readings?

 

[Douglas.Curtis]

I'll have to find the link to the study where something like 65F was found to be optimal for cannabis growth rates. I prefer a max canopy temp of 70F, but then I'm the odd one.

 

[Cmoon]

He means staggering individual lights on and off throughout the 12hr light cycle so that only X number of lights are on at any given time. X being the number of lights you can run and keep the temp where you want it.

I definitely wouldn’t do a full 12hr switch to flip the actual time of day your lights are coming on.. that’s asking for trouble like you said. Definite hindsight is 20/20 situation.. it happens.. now ya know

yes m8, not changing the light cycle just reducing the number of lights lit, but bigger extractions key

 

[maryjanesdad]

As hot as 28c, the optimum leaf temperature for cannabis growth?

I wouldn't want to grow at 72-76. I mean.. 72? I just couldn't. That's not even the design temperature for watching TV.

Where are you taking these readings?

I have always aimed to keep room temp in the mid 70s and not have more than a 8 degree change in temps from day/ night. As for canopy temperature, I dont have my own infrared heat reader but when last time canopy temps were high 70s.

I'm using a $20 thermometer that's on my wall. I'm sure it's not the most accurate but it's what I have available.


What temps do you aim for when blooming?

 

[maryjanesdad]

Update:

I dimmed 2 lights to 400w capacity and it seems to fix my high temp problem. I still plan to increase outtake fan to 10in.

 

[Cmoon]

Update:

I dimmed 2 lights to 400w capacity and it seems to fix my high temp problem. I still plan to increase outtake fan to 10in.

yep, way to do it with variable ballasts...lifting lights a foot more than normal if poss will help but only while you wait on a fan


bests cmoon