Water uptake is almost at zero.

[LeastExpectedGrower]

I had to do this exact same thing to keep all my issues at bay and since setting it all up couple years back it’s been amazing for my setup. I’m sure there is other ways to achieve this same goal but for the low cost of a heater and ink-bird it’s well worth it.

This is one of those things you have to deal with and depends on your personal environment. If your room is 'hot' or your tent is in a hot location, then you probably don't need a heater, but you may need some kind of AC. In my case the fans will take care of the heat ceiling most of the time. I've been laying off growing during July/August because I have a basement level grow and to control humidity I run dehumidifiers in our basement level that drives up temps by about 10f degrees, making in-tent lights on temps go up a bit higher than I'd like. The rest of the year, the temps at basement level are 60's and 70's, which gives me a chance to stay in the right environmental conditions with some lights out heating and programmable fans.

I actually can moderate some temps by literally leaving the door to our utilities room open or closed. Closed and the boiler heats the room when it's running...or right now, since I'm drying I leave the door open and the tent is staying @ 58-61 degrees.

Humidity is another thing. I find it easier to dehumidify outside the tent and humidify inside the tent. That's because dehumidifiers also bring heat while humidifiers don't. I have an inkbird for my humidifier as well, but these days use an AC Infinity smart outlet and Controller 69 Pro for that function...because it uses the same sensor so the triggers to humidify or kick up the fans to dehumidify are based on the exact same sensor reading.

 

[Fishmon]

Thanks bud and I'm doin exactly that. I'm keeping my humidity at 45% and a fan blowing 24/7
As I worked thru his advice I couldn't bring myself to raise the cabinet temperature that much. It's happy as hell with the current temperature range. I just don't understand how it can go 7-8 days with drinking up it's content of water. Other than that, she's a sticky and happy little girl and looking like she'll be very frosty

I had a sour diesel that slowed way down in uptake for a few weeks. Otherwise looked fine. Afterwards it went back to business as usual. Only theory I could muster was it just wanted to ride in the slow lane for a spell. It was further into flower than yours. My temps got out of whack a couple times in flower mid 80s+ and I wound up with varying degrees of foxtail on a couple other runs so I try for mid to upper 70s even 80 day and low 70s night. Working for me. I'm still fairly new to indoor so my goal is to get across the finish line with a happy plant. More experienced growers are better able to push the plants harder but until I'm better at it I'm satisfied with the results I've been blessed with of late.

 

[Texas Growing Crew]

The temperature adjustments will jelp, 82 is the new 72 under LED. If your night temps get to kool it will slooo9wwww down. Mine will slow their drinking around 30 so I add a tad bit of humid acid, good humid derived in laboratory helps it uptake little better but too much could cause issues. Went from sluggish to standing praying leaves overnight. I feed with dry amending through

 

[Texas Growing Crew]

The temperature adjustments will jelp, 82 is the new 72 under LED. If your night temps get to kool it will slooo9wwww down. Mine will slow their drinking around 30 so I add a tad bit of humid acid, good humid derived in laboratory helps it uptake little better but too much could cause issues. Went from sluggish to standing praying leaves overnight. I feed with dry amending through

Humic Acid, autocorrect makes my writing look like a 4 yr old!

 

[Texas Growing Crew]

This is 1 week later still reaching for the heavens. Both are Mean Gene's work. The BLR has stacks building up and I'm barley 27 days.

 

[calvin.m16]

Yes raise your temperature to at least 80. 85 is fine. But 70 is just not warm enough for LED

Not sure why 85 °F in flower? Seems hot..

Here is where people get confused. I agree with @hotrodharley , You want 80+ running LEDS. Most manufacturers say something like;
"Flowering temperature is ideally at 84 - 85 °F. This will help keep leaf temps at the Cannabis-ideal 88 degrees when using our LED grow lights. Vegetative temperatures can range from 75°-90°. However, ideal vegetative growth will occur at 85 °F and 60-70% humidity." -- From Black Dog LED
"LED's emit no IR, so to achieve similar metabolic rates found in HID or greenhouse conditions at 78F air temp,LED growers need to run the room air temp at 83F-85F." -- CA Lighting

The problem with this is most articles that recommend 85 °F in flower are usually selling LED lights. Where is an article that proves this hot of temperature is ideal by someone that doesn't sell LED and want to push the less HVAC shenanigans. I'm not trying to be a contrarian but some of my best runs with LED have been where temps never exceeded 80 and never went below 70. ¯\_(ツ)_/¯

 

[hotrodharley]

Not sure why 85 °F in flower? Seems hot..



The problem with this is most articles that recommend 85 °F in flower are usually selling LED lights. Where is an article that proves this hot of temperature is ideal by someone that doesn't sell LED and want to push the less HVAC shenanigans. I'm not trying to be a contrarian but some of my best runs with LED have been where temps never exceeded 80 and never went below 70. ¯\_(ツ)_/¯

I said 80 eh? I’m sure you see that. The 85 is in preference to 70.

 

[Delps8]

70's is fine for LED, you do not want your temps at 85. Bad advice from chronic bad advice giver.

Just let the plant dry some and try to increase air movement by putting a fan so it blows across the top of the soil.

Cannabis will do just fine at 85. It's arguable that 86° will maximize photosynthesis. Check the Chandra paper - that's a CO2 enhanced environment but that's not a confounder. My fan comes on at 84° for my current grow.

At the other end of the scale, 70° - yikes. That's low. Cannabis will grow at that temp but everything slows down.

Ambient emperature is only part of the equation. The complement to temperature is RH. And then there's leaf temperature, too. Put them together to get VPD and keeping VPD in range is more important than hitting a given temp.

 

[DrDukePHD]

Cannabis will do just fine at 85. It's arguable that 86° will maximize photosynthesis. Check the Chandra paper - that's a CO2 enhanced environment but that's not a confounder. My fan comes on at 84° for my current grow.

At the other end of the scale, 70° - yikes. That's low. Cannabis will grow at that temp but everything slows down.

Ambient emperature is only part of the equation. The complement to temperature is RH. And then there's leaf temperature, too. Put them together to get VPD and keeping VPD in range is more important than hitting a given temp.

So if humidity is 35% you probably don't want to keep your tent at 83 lights on, maybe drop it to 79?

 

[Delps8]

To each their own respectfully. I've run 85°f and I can tell u for sure now running at 77° is 100% better. Better smell and taste in final product. I stay between 74-78°. 85° should be max. High temps can destroy trichs. Colder temps also bring out plant colors. Same reason u keep drying temps low is to preserve trichs.

Funny you bring that up…

Bugbee, per another poster, talks about temps in the mid-80's because that where photosynthesis is maximized (lookup the paper by Chandra and check net P curve). In contrast, one of Bugbee's students, Mitch <fill in the last name> did a YouTube on cannabis growing and he said that same as you did - trichomes got stomped when temps went over…

[time passes]

Spotlight rocks.

My notes from the video are below. They're unedited and what I captured, unquestionably, is a result of my biases so it might be a good idea to watch the video yourself.

"

Does Hemp Need Extra Water and Fertilizer?
Mitch Westmoreland

Discusses temperature - Optimum temp to maximize CBD and yield and keep THC below 3%

plants grown at 73 and 84 degrees. Plants at 84 were taller but colas were smaller in girth.

At 84 little but taller, a bit more vegetative biomass. Yield wasn't all that affected by the increase tempearature. At 84%, cannabanoids were roughly 1/2 of what they were at cooler temperatures.

Suggest that the optimum is between 70 and 80.

Fertilizer
You've probably come across hundreds of companies promising to boost yield. They "lack a theoretical basis" and you'll probably end up just throwing away money and excess nutrients that will end up polluting our nice rivers.

We recomend that you fertilize it just as you would tomatoes. This is a good comparison there's nothing particularly special about hemp.

One of the big claims that you'll see coming out out of the cannabis industry is that high phosphorus will increase yield and will increase cannabanoid content. We've tested this.

We look at a range of phosporus treatments ranging from borderline deficient to excessive. We found no significan difference, especially as we move toward the rates recommended by the cannabis industry. This has implications because phosporhus is a potent pollutant in our environment.

What we're trying to do is get growers to use as little P as we can while still getting a good crop.

Drought stress
In veg - they're very resiliant. Got to the point where they were severely wilted. They recovered so that it seems as if nothing happened. Hard to see which one's were stressed and while ones were well watered.

In flower - yellowing and dropping of leaves and reduction in yield. CBD and THC does not make production increase.

Temperature - yield increased slightly. CBD and THC plummeted - "cut in half basically". We don't have a good explanation for this right now. We're going to ssee if we can reproduce this and see if we can come up with an explanation for what's going on."

 

[madvillian420]

Funny you bring that up…

Bugbee, per another poster, talks about temps in the mid-80's because that where photosynthesis is maximized (lookup the paper by Chandra and check net P curve). In contrast, one of Bugbee's students, Mitch <fill in the last name> did a YouTube on cannabis growing and he said that same as you did - trichomes got stomped when temps went over…

[time passes]

Spotlight rocks.

My notes from the video are below. They're unedited and what I captured, unquestionably, is a result of my biases so it might be a good idea to watch the video yourself.

"

Does Hemp Need Extra Water and Fertilizer?
Mitch Westmoreland

Discusses temperature - Optimum temp to maximize CBD and yield and keep THC below 3%

plants grown at 73 and 84 degrees. Plants at 84 were taller but colas were smaller in girth.

At 84 little but taller, a bit more vegetative biomass. Yield wasn't all that affected by the increase tempearature. At 84%, cannabanoids were roughly 1/2 of what they were at cooler temperatures.

Suggest that the optimum is between 70 and 80.

Fertilizer
You've probably come across hundreds of companies promising to boost yield. They "lack a theoretical basis" and you'll probably end up just throwing away money and excess nutrients that will end up polluting our nice rivers.

We recomend that you fertilize it just as you would tomatoes. This is a good comparison there's nothing particularly special about hemp.

One of the big claims that you'll see coming out out of the cannabis industry is that high phosphorus will increase yield and will increase cannabanoid content. We've tested this.

We look at a range of phosporus treatments ranging from borderline deficient to excessive. We found no significan difference, especially as we move toward the rates recommended by the cannabis industry. This has implications because phosporhus is a potent pollutant in our environment.

What we're trying to do is get growers to use as little P as we can while still getting a good crop.

Drought stress
In veg - they're very resiliant. Got to the point where they were severely wilted. They recovered so that it seems as if nothing happened. Hard to see which one's were stressed and while ones were well watered.

In flower - yellowing and dropping of leaves and reduction in yield. CBD and THC does not make production increase.

Temperature - yield increased slightly. CBD and THC plummeted - "cut in half basically". We don't have a good explanation for this right now. We're going to ssee if we can reproduce this and see if we can come up with an explanation for what's going on."

Wouldnt every single parameter of this experiment need to be recalculated if there was variation in the strains used? different strains and even different phenotypes of the same strain can show signs of deficiency if all fed the same amounts and some plants require a modified feeding schedule to correct this, dont they?

 

[calvin.m16]

Funny you bring that up…

Bugbee, per another poster, talks about temps in the mid-80's because that where photosynthesis is maximized (lookup the paper by Chandra and check net P curve). In contrast, one of Bugbee's students, Mitch <fill in the last name> did a YouTube on cannabis growing and he said that same as you did - trichomes got stomped when temps went over…

[time passes]

Spotlight rocks.

My notes from the video are below. They're unedited and what I captured, unquestionably, is a result of my biases so it might be a good idea to watch the video yourself.

"

Does Hemp Need Extra Water and Fertilizer?
Mitch Westmoreland

Discusses temperature - Optimum temp to maximize CBD and yield and keep THC below 3%

plants grown at 73 and 84 degrees. Plants at 84 were taller but colas were smaller in girth.

At 84 little but taller, a bit more vegetative biomass. Yield wasn't all that affected by the increase tempearature. At 84%, cannabanoids were roughly 1/2 of what they were at cooler temperatures.

Suggest that the optimum is between 70 and 80.

Fertilizer
You've probably come across hundreds of companies promising to boost yield. They "lack a theoretical basis" and you'll probably end up just throwing away money and excess nutrients that will end up polluting our nice rivers.

We recomend that you fertilize it just as you would tomatoes. This is a good comparison there's nothing particularly special about hemp.

One of the big claims that you'll see coming out out of the cannabis industry is that high phosphorus will increase yield and will increase cannabanoid content. We've tested this.

We look at a range of phosporus treatments ranging from borderline deficient to excessive. We found no significan difference, especially as we move toward the rates recommended by the cannabis industry. This has implications because phosporhus is a potent pollutant in our environment.

What we're trying to do is get growers to use as little P as we can while still getting a good crop.

Drought stress
In veg - they're very resiliant. Got to the point where they were severely wilted. They recovered so that it seems as if nothing happened. Hard to see which one's were stressed and while ones were well watered.

In flower - yellowing and dropping of leaves and reduction in yield. CBD and THC does not make production increase.

Temperature - yield increased slightly. CBD and THC plummeted - "cut in half basically". We don't have a good explanation for this right now. We're going to ssee if we can reproduce this and see if we can come up with an explanation for what's going on."

This vid he says 82-62% and he's clearly having good results.

 

[Delps8]

Wouldnt every single parameter of this experiment need to be recalculated if there was variation in the strains used?"
"need" - no. The research stands on its own (I would hope). What readers do with the data is up to each reader and the reader would be wise take into account his level of understanding of plant science when drawing conclusions.
Though there are different strains of cannabis, they're all from one species (according to some botanists) but, even if you consider sativa, indica, and ruderalis to be fundamentally different, their systems still function in exactly the same manner for the most part. It's fine to try to draw distinctions but it's very hard to come up with the right answer unless the individual has the knowledge needed to do so.

" different strains and even different phenotypes of the same strain can show signs of deficiency if all fed the same amounts and some plants require a modified feeding schedule to correct this, dont they?

I'm sure that, at times, that's correct but what does research show?

When clones are grow in a controlled environment, you will tend to get the same results. As soon as you deviate from "clones grown in the exact same environment" you will tend to not get the same results because you've introduced variances.

My take - there are so many inaccuracies in almost all aspects of home growing it's hard to say one way or the other. It's very hard to remove those variances and, since cannabis is an incredibly bountiful plant, we still end up with a good harvest.

Simple case in point is how hard it is to consistently measure PPFD. The issue there is that changing the height of a PAR meter sensor by just a few millimeters results in a significantly different value. For growers who not using an Apogee or a Li-Cor (I don't know about Spot On) are getting even more inaccurate results.

Again, what makes up for those variances is that cannabis is so prolific.

Re. "signs of deficiency" - soil's tough (I'm a hydro guy) but I'll hedge my bets with Bugbee - the big cause of nutrient deficiencies not because the nutrient mix is off - it's either environmental conditions or your nute level is too high. Another factor to keep in mind is that fertilizers have ranges of concentrations of the individual chemicals and that's fine because accuracy is helpful, not vital. The goal with nutes is to get the plant in the "sufficiency" range of concentrations of chemicals in the plant. Many growers believe that "more is better" so they add "more". Or, lacking an understanding of VPD, they think their nutes are "bad" but, since they have zero clue about VPD, they don't realize what's causing their problems.

 

[Delps8]

This vid he says 82-62% and he's clearly having good results.

Cannabis will give great results under a range of conditions. There's no magic, despite what vendors claim (they're as honest as the companies that sell supplements for humans) - if you keep a grow within a range of conditions, cannabis will do well.

82 and 62 are right in the ballpark. The key point for VPD measurement is leaf surface temperature, rather than ambient temperature, and there are seven other factors that make up the grow environment.

 

[Phytoplankton]

The low temp gets down to the lower 70's and tops out around 83. The top leaf temps stay around low 70's.

That's just fine!