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Questions With LED's and CO2 how hot is too hot?

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Hello, I'm a newbie to the forum but have been growing for years. I recently moved and switched to LED (HLG 600 RSPEC). My new house has an insulated 10x10 shed (I'm in Canada) and I have an AC Infinity 5x5 going in there. I just came home from work and it's 29 degrees out and my tent is at 33 degrees. I've heard that you can run a little hotter with LED and even hotter if you add CO2. Does anyone have experience with this? I don't have CO2 currently but am not opposed to getting it. I'm wondering if anyone knows how hot I can get away with having an LED/CO2 combo? I'm trying to avoid running an AC unit in the shed because I think I'd need to add another breaker and I'm renting and would rather not have to mess with the existing electrical. Any thoughts would be greatly appreciated. Thanks!

Posted : May 30, 2023 10:15 pm
Stootie, Brownthumb, monkeydo and 5 people reacted
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@stoneymagee welcome to Percys mate, thanks for joining us. To start with, it might seem a bit hot, but the plants can get way warmer as long as the humidity is at the right levels. Dont worry about the CO2 right now. Thats a bit too much for a home grow.Β 

Can you get a pick of the plants up? Look for the leaves "canoeing". This is when the edges of the leaves sort of curl upwards, meaning they are under heat stress. But I have seen tents go over 35c and have no issues. So dont panic too much Smile Get a pic up if you can so we can have a look at the plants.Β 

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Posted : May 30, 2023 11:34 pm
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@stoneymagee I have heard people say that some volatile oils in buds can evaporate above 30c/85 F, but I don't know this to be true.Β  CO2 is definitely helpful for a grow, but I have always heard of this being used in the context of high light levels and not related to temp. I am not saying it is not, I just have not head of that before. Generally you need CO2 when your DLI gets above 30-45 DLI. Hope that helps.

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Posted : May 31, 2023 1:32 pm
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@stoneymagee I run the same light, if its getting up around those temps raise the humidity a few points to around 60% and keep an eye on the leaves for canoeing as @macky mentioned. I have had my tents spend a good week at 35c+ (Aussie heat is relentless) usually they are fine if I keep the feeds up and raise that humidity a touch. Make sure you have plenty of air movement in there also so that the leaves are getting cooled, its the stagnant leaves not moving around that will be the first to burn. C02 is only going to help if you can keep the system closed and with temps like that if your extractors are running flat out you will see larger spikes if you turn it down compensating for the c02. C02 is something that should be added if everything is spot on and even then its not going to help your situation realistically. A good trick is to get a bag of ice, a bucket, a small fan and a cardboard box, cut a 4" hole in one side and a hole large enough for a small fan on the other, seal up the box with the bag of ice inside in the bucket, then get a fan blowing into the box and it will blow the cold air out the other side, like a poor mans a/c. it will at least bring your temps down a few points at the hottest part of the day.Β 


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Posted : May 31, 2023 1:36 pm
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@stoneymagee, I run my plants at night. They wake at 8pm and they sleep at 8am, flower, but you can do the same with veg. To change them just leave the light ON if your in veg till the time comes to shut off (all night) or for flower leave them in the dark till time for morning comes around. Either a long day or a long night but then your in the cooler part of the day.

Posted : May 31, 2023 2:28 pm
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