Best temperature range for growing cannabis?

[Connoisseurus Rex]

So, lets look at this like a math problem.. Not my strong point, if you know statistics, I could use some pointers.

I took the values for growing temp for lights on, no co2 and found the middle range for example 77-80, I split the difference.. 78.5 for example.

Here's the values I got from the thread. Based off of community answers.

78.5, 76.5, 75, 85, 75, 84.5, 77, 67, 73.5, 77, 78.5, 74.3

So I applied the standard deviation formula, https://www.easycalculation.com/formulas/standard-deviation.html

76.81 F Is ideal, +/- 4.5 F to stay within the optimum range.​

(+/- 10F in my opinion, round up or down +/- 1F from 76.8 should be ok... again more opinion.)​

So lets look at the chart, for VPD, so at that temp we could run about 60%RH.

I didn't add my answer because I didn't want it to be biased, but I like the higher 70's mainly as a cushion in case of malfunction. But I dont use that much precision myself I dont have datalogging.

Sounds about right. Most plants can handle temps between 55F and 105F with decent stride in my experience. Plants don't rely on just temperature alone to thrive. Other environmental factors are much more important in my opinion.

Transpiration works around several factors. Too much, too fast... Cavitation. Too little, too slow... Stunted growth.

So to me, it's not a temp thing. It's a transpiration balance thing.

 

[Carolina Dream'n]

I run high temps and love it. 88-92 in veg with 70-75% humidity. Co2 at 900 ppm.
I'll drop my temps down about 2 degrees a week in flower from that. Ending at about 76-78 degrees the last week. Humidity slowly drops with temps down to 50%. Co2 peaks at 1300 ppm week 4-5 of flower and drops back to 900 by the last week of flower.

Night temps are a standard 68-70 degrees at all times and 40-50% humidity. Night time co2 levels are 300-400.

 

[GrowerGoneWild]

Sounds about right. Most plants can handle temps between 55F and 105F with decent stride in my experience. Plants don't rely on just temperature alone to thrive. Other environmental factors are much more important in my opinion.
So to me, it's not a temp thing. It's a transpiration balance thing.

Well, I'm observing alaskans growing Ruderalis hybrids outside, or at least finishing them outside in the summer months, we can say there must be a population that does well in lower temps. As long as you are making unbiased observations on what works best, but your 67F temp is on the low end of the temp looking at the community average I came up with. Im not telling you that you are wrong or right.. Its just an observation.

 

[qwizoking]

temperature has much more to do with biological processes than simply transpiration. any and all enzymatic activity, terpene development, formation/uptake of nutrients and products in the plant as well as efficiency of, including photosynthesis, chlorophyll formation etc etc. bacteria are working harder. i mean everything is sped up with increased heat.



i have nothing else to say on tjhe matter, not really paying attention. just throwing out that temp doesnt simply effect water uptake and transpiration.




ive had seedlings and harvested in freezing temps with a few inches of snow. ive had seedlings and harvested in +100° temps. the plant is hardy, its hard to be objective aboutbgrowth without running clones and trials.

many of us experienced growers have actually done just that

 

[Connoisseurus Rex]

Well, I'm observing alaskans growing Ruderalis hybrids outside, or at least finishing them outside in the summer months, we can say there must be a population that does well in lower temps. As long as you are making unbiased observations on what works best, but your 67F temp is on the low end of the temp looking at the community average I came up with. Im not telling you that you are wrong or right.. Its just an observation.

Nah, it's cool. Relative temp is 59F right now at 5 days old. Canopy is at 73. They love it. Transpiration man. Nice gap between root and canopy temp makes them sweat haha.

I don't grow like everyone else. I prefer my steak medium well. Bet a lot of growers would disagree. As long as we don't go hungry, I don't see an issue.

 

[Connoisseurus Rex]

temperature has much more to do with biological processes than simply transpiration. any and all enzymatic activity, terpene development, formation/uptake of nutrients and products in the plant as well as efficiency of, including photosynthesis, chlorophyll formation etc etc. bacteria are working harder. i mean everything is sped up with increased heat.



i have nothing else to say on tjhe matter, not really paying attention. just throwing out that temp doesnt simply effect water uptake and transpiration.




ive had seedlings and harvested in freezing temps with a few inches of snow. ive had seedlings and harvested in +100° temps. the plant is hardy, its hard to be objective aboutbgrowth without running clones and trials.

many of us experienced growers have actually done just that

I didn't say temps weren't important. I just feel that other factors outweigh temps. Just like your experience has shown. Temps aren't the end all be all of growing.

 

[whitebb2727]

Yea. I've run all the way up to 80 for seedlings. I like to stress them out of the gate. Growth rate in the seedling stage, at least in my experience, grows hardier when raised in true spring temperatures. These fuckers pop when night temps are still going down into the 40s and day temps may only reach low 50s with only a few hours of light here and there.

They thrive in nature. Ever seen an outdoor grow? It's not just because of the lighting. A side by side grow, same pot size, same nutes, just one outside and one inside with the best light in the world. I'll put my money on the outdoor for the best grow.

The more stress you put on them, the hardier they will be, the more resilient they will be and the stronger they will grow. Just my experience though.

Used to guerilla grow like this. Put 6-8 plants in one spot with the goal of keeping 1-2.

I plant outside in spring with cool temps every year. Summers over 100. Wild temps swings in the fall.

 

[GrowerGoneWild]

Nah, it's cool. Relative temp is 59F right now at 5 days old. Canopy is at 73. They love it. Transpiration man. Nice gap between root and canopy temp makes them sweat haha.
I don't grow like everyone else. I prefer my steak medium well. Bet a lot of growers would disagree. As long as we don't go hungry, I don't see an issue.

I have no opinion on how you run your garden, I'm looking at is the range based on community numbers, I'd like to do a light depro greenhouse, I'm trying to see the limits on temps. Kinda using your numbers as a reference.. If you can do it at 67, (and it seems possible looking at the math) why cant I? .

 

[Connoisseurus Rex]

You absolutely can. Weed will continue growing down into the 40s.

My point was, everyone grows differently. You can produce plants grown in the 50s that will be just as impressive as ones grown in the 80s. Temp isn't a deal breaker.

 

[Connoisseurus Rex]

Used to guerilla grow like this. Put 6-8 plants in one spot with the goal of keeping 1-2.

I plant outside in spring with cool temps every year. Summers over 100. Wild temps swings in the fall.

Same here. I will admit though, I do baby my outdoor plants a little with some shade in the heat.

 

[ryan1918]

I run high temps and love it. 88-92 in veg with 70-75% humidity. Co2 at 900 ppm.
I'll drop my temps down about 2 degrees a week in flower from that. Ending at about 76-78 degrees the last week. Humidity slowly drops with temps down to 50%. Co2 peaks at 1300 ppm week 4-5 of flower and drops back to 900 by the last week of flower.

Night temps are a standard 68-70 degrees at all times and 40-50% humidity. Night time co2 levels are 300-400.

Yeah that's 20 degrees difference that seems like a lot

 

[Carolina Dream'n]

Yeah that's 20 degrees difference that seems like a lot

Stating what I do. Don't think it's a good idea, don't try it.

 

[HydroNito305]

So according to this VPD chart, as long as I keep my RH% inbetween 75% and 80%, then for the most part I pretty much can't go wrong no matter what temperature I'm in... is this correct?

 

[ryan1918]

temps are very low last night 15° and was 55° when my lights were off but they all looked rather well

 

[Connoisseurus Rex]

temps are very low last night 15° and was 55° when my lights were off but they all looked rather well

As long as you keep your humidity in check, they're fine in low temps.

 

[qwizoking]

lol

 

[Connoisseurus Rex]

lol

I know, I know. I cold grow all the time though. Never any issues. Got sick of contending with winter temps and just learned to grow in them.

 

[ryan1918]

gotta love Michigan for you!

 

[mean.green]

my temps range from 66 degrees with the lights off, up too 85 degrees with the lights on. I try to keep the temp below 80 degrees but 250 watts of cfl runs pretty hot.

 

[coughphee.connoiseur]

Hello if anyone I decided to direct my question here instead of creating a thread about this. If anyone is still following this thread and could provide reliable expertise.

I have concerns about daytime ( lights on temp. flux.) I have just ran testing, but with the A/C set to 66-68 with the lamp power maxed out the temperature fluctuates consistently between 70-80 every 5-10 minutes.

This seems like a lot of stress on the A/C system, yeah? and also concerns me a little about the stress on the plant.

Normal and I'm just over thinking? or should i make some adjustments?