What temperature and rh are you running at?
Fudo Myoo's Organic, LED Homegrown Journal
- Thread starter Fudo Myoo
- Start date
Nice score on the new Mars!
Perfect time to fold it in half!
- Thread starter
- #923
Fudo Myoo
Well-Known Member
73F, about 70H. Humidity fluctuates. It’ll hit low 70’s after water and stay there awhile. Until they start drinking more anyway.
- Thread starter
- #924
Fudo Myoo
Well-Known Member
That’s a great idea!
I would bump that up to 78f and 65-70rh At 73 and 70 your plants are struggling to breathe properly. The air is so thick they can’t transpire efficiently, causing them to wilt. They’re essentially suffocating. They can’t evaporate water out of the stomata quickly enough due to the level of moisture in the air causing less than ideal pressure within the plant, hence the wilting/sad look.
That’s a .4 kPa which is a brutal room VPD for anything other than a clone trying to root. At this stage you want right around 1.0. It’s likely your plants actual VPD is even lower than this since it’s leaves are typically 2-5 degrees cooler than the room temp.
I would bet a lot that if you raised the temps (or lowered the rh by 5-10 percent; temps would be a better choice) you’d see a noticeable improvement
Edit: I added extra info and changed the formatting
- Thread starter
- #926
Fudo Myoo
Well-Known Member
Thanks, I’ll give it a try. I can kick up the exhaust and use my heater if I need to.
If you have a wireless hygrometer it’s likely tracking your vpd. This won’t be super accurate but it gets you in the ballpark. Or you can just use a chart and ballpark it. If you wanna get serious you can buy an ir thermometer for 16$ on Amazon and measure your leaf surface temp yourself.
Start charting or observing the differences in your plants behavior at different temps and humidity. You’ll notice some strains like it hot and swampy, 80-85f and 70-80rh. Some like it 78 and 65, some maybe a little cooler or hotter or more humid or dryer. They typically vary by strain but they all seem to respond well to at least 78f and 65-70rh in my experience. You will often see them adapt quickly, within the hour. Some times I see it within 30 minutes.
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- #928
Fudo Myoo
Well-Known Member
Hey @Keffka, I’ve had this chart saved for awhile but completely forgot what it represents, other than green=good. According to this I was in the ballpark. Isn’t it the best range for photosynthesis?
That being said, it’s been 2 days since water so the humidity fell to 64H and they do look better. A little more lift I think.
That being said, it’s been 2 days since water so the humidity fell to 64H and they do look better. A little more lift I think.
Hey @Keffka, I’ve had this chart saved for awhile but completely forgot what it represents, other than green=good. According to this I was in the ballpark. Isn’t it the best range for photosynthesis?
That being said, it’s been 2 days since water so the humidity fell to 64H and they do look better. A little more lift I think.
Those numbers don’t make sense lol. I’m not sure what unit they’re in since kPa is typically a range of something like 0.1-5.0 and we as growers want to be around 1.0 depending on the stage of growth, lower if younger, higher if older. However, the color suggestions are close to accurate. Remember though, propagation and early veg are different than late veg. Those plants are technically in late veg when looking at the charts.
Here is a bit better of a chart, easier to use anyway, it’s a bit more oriented toward the room itself:
According to that chart, at 70f and 73rh the plants were around .65-0.7 which is even kind of low for propagation. Lower than I prefer anyway.
Your plants already look a bit better under dryer conditions. Not as droopy/wilty looking. However they’re beat up so they’ll take a few days to really get going.
One thing you gotta remember is your leaf temperature is typically going to be 2f-5f degrees colder than your room temp. So if the chart says 70f and 60 rh then you want your room to be somewhere around 72-75 to actually hit that number. Pay attention also to how many points rh goes up for every degree increased. Usually for every degree you want 2-3 more points in rh. If you use the chart I linked, it’s more focused on your actual room measurements so no need for mental math, just follow the chart as is.
Another thing to remember is, at certain temperatures your soil biology slows down, and your plants photosynthesis slows down. So while the VPD is good when you’re at 70f and 60rh, the soil biology is slowed down and the plant isn’t photosynthesizing as best as it could. This means your plant can now breathe and move nutrients properly, however it’s cold. Just like us, it won’t be able to perform at its best when cold.
Here’s a perfect example. Last night I forgot to switch my heater over so my room was at 70f and 73 rh, here’s the plants at that range
Here are the plants at 78 and 68
You can see the difference in their vitality just based off the environment. If I made it dryer or hotter they would raise up even more. I don’t want that though since I’m running organic I need the plant and biology to work together. Running it too dry in such small containers will force the plant to move water faster than it can take up nutrients like calcium
Here are the plants at 78 and 68
You can see the difference in their vitality just based off the environment. If I made it dryer or hotter they would raise up even more. I don’t want that though since I’m running organic I need the plant and biology to work together. Running it too dry in such small containers will force the plant to move water faster than it can take up nutrients like calcium
- Thread starter
- #931
Fudo Myoo
Well-Known Member
Right now it’s at 72F, 66H.Here’s a perfect example. Last night I forgot to switch my heater over so my room was at 70f and 73 rh, here’s the plants at that range
Here are the plants at 78 and 68
You can see the difference in their vitality just based off the environment. If I made it dryer or hotter they would raise up even more. I don’t want that though since I’m running organic I need the plant and biology to work together. Running it too dry in such small containers will force the plant to move water faster than it can take up nutrients like calcium
Interesting! Epsoma is a major player! I don't know what to say. I know I was focussed on magnesium there for a while.False advertising!
Maybe I was wrong to say dolomite was necessary. I thought it was. Here's another source I just found on soil ph raising. https://vric.ucdavis.edu/pdf/soil/changingphinsoil.pdf
Looking at the article you may be right with both. Somewhat. Far as I know garden lime is different. That Espoma Garden lime isn't the garden lime I buy to drop on my lawn by the 40 pound bag. It is indeed dolomite lime.
I would Fudo. I just put one in and am going to top water it until it really roots well before I start filling the rez. It may have a slow period when I do fill but I think it'll be worth it!
Gee64
Well-Known Member
Mornin' Fudo. 
️.
Here is a pic of your leaves on a couple of your plants. Look closely at the ones I circled.
See the mottling effect of lighter/darker green in the circles? A blotchy look? That is an indiicator that your plant is too cold.
Water isn't transpiring properly, it's too slow. That's why they have that over watered droop to the leaves. They may not actually be overwatered by you, but if they take in more water than they can exhale, they get droopy. Slow moving water means slow moving food as well.
If you can get your room temps up to 78 and adjust your light intensity to get your leaves to 75 or 76, 2 or 3 degrees less than air temps, with an RH of 65%, Your issues should resolve themselves in about 48 hours.
Once they start to transpire better, the effect will snowball in your favor as the water comes out of the plant.
Warm air has the ability to hold more moisture (it's dryer) than cool air, it's why clothes dryers use warm air, and water always flows from wet to dry, so warmer drier air will attract moisture faster.
The moisture in your pot is attracted to that drier air, and the dry air will suck on the plant's stomata like a straw, drawing the water in your pot thru the roots (laden with soil nutes) and into the plant, thru the plant's vascular system, and out the stomata in the leaves. You need to warm your air to increase that suction (VPD) to get the water moving out of those water-fat leaves.
If the air sucks too hard the plant will constrict the stomata to try to slow the process, and that works but, the stomata openings let both water out, and CO2 in, so too dry of air will suck too hard, constricting stomata, and CO2 intake gets restricted.
So it's a balancing act. In that whole process, if the leaf is 2 -3 degrees cooler than air temps, the rate of transpiration to atmosphere, which is really just evaporation moving thru your plant, is optimal if your room temps are in a good range of about 76F-80F in veg, allowing stomata to open wide for gas exchange in both directions, water out and CO2 in.
I prefer a room temp of 78F myself, with a leaf temp of 76 and 65% RH, for a plant that size, giving a VPD of .94, which is great for their level of maturity.
First you need your air temps up. That will automatically change your RH in the grow room, thus your VPD as well, so after it warms adequately, then start adjusting light intensity for leaf temp offset ranges ( that 2-3 degree difference), and your room RH. Make these adjustments slowly over a few days.
Don't chase leaf temps or room RH until the room temp comes up, as it's a moving target as the temps are increasing.
Leaf temps will naturally fluctuate a lot from lights on until about 10 hours into the day.
At around the 10 hour mark after lights on is when you want to take your readings that you will use for adjustments. Don't make adjustments early in the day. You want to make adjustments to cater to when the plant is working hardest, pushing it's limits.
Warm that room and things should really come around, then let them dry down for a couple waterings until you stabilize your atmosphere and get used to their new watering needs, and then find the sweet spot on pot moisture levels to stabilize the whole process.
The 3 really droopy clones also look like the myco didn't take, so to be sure, if they were mine, they would get a myco root drench mixed as per the myco instructions. In a week that myco drench should be having an effect. Drench them all if you like, it won't hurt, but warm the air to dry the plants down a bit 1st.
The one plant on the left is doing fine, so I would suspect it is heavily Indica leaning, as indicas can handle cooler temps better. It may also have a healthier mycellium in the pot.
Add heat, then go from there.
Sometimes trying to stabilize room temps will drive you nuts. If you can't get it to stabilize, try using a heating mat under your pots to warm them a bit. I usually set mine for 76F if I need them. Warming all that dirt creates a good stable heat sync in the room. It stops fluctuations AND increases microbe/fungii populations.
They will be ripping in no time.
️.Here is a pic of your leaves on a couple of your plants. Look closely at the ones I circled.
See the mottling effect of lighter/darker green in the circles? A blotchy look? That is an indiicator that your plant is too cold.
Water isn't transpiring properly, it's too slow. That's why they have that over watered droop to the leaves. They may not actually be overwatered by you, but if they take in more water than they can exhale, they get droopy. Slow moving water means slow moving food as well.
If you can get your room temps up to 78 and adjust your light intensity to get your leaves to 75 or 76, 2 or 3 degrees less than air temps, with an RH of 65%, Your issues should resolve themselves in about 48 hours.
Once they start to transpire better, the effect will snowball in your favor as the water comes out of the plant.
Warm air has the ability to hold more moisture (it's dryer) than cool air, it's why clothes dryers use warm air, and water always flows from wet to dry, so warmer drier air will attract moisture faster.
The moisture in your pot is attracted to that drier air, and the dry air will suck on the plant's stomata like a straw, drawing the water in your pot thru the roots (laden with soil nutes) and into the plant, thru the plant's vascular system, and out the stomata in the leaves. You need to warm your air to increase that suction (VPD) to get the water moving out of those water-fat leaves.
If the air sucks too hard the plant will constrict the stomata to try to slow the process, and that works but, the stomata openings let both water out, and CO2 in, so too dry of air will suck too hard, constricting stomata, and CO2 intake gets restricted.
So it's a balancing act. In that whole process, if the leaf is 2 -3 degrees cooler than air temps, the rate of transpiration to atmosphere, which is really just evaporation moving thru your plant, is optimal if your room temps are in a good range of about 76F-80F in veg, allowing stomata to open wide for gas exchange in both directions, water out and CO2 in.
I prefer a room temp of 78F myself, with a leaf temp of 76 and 65% RH, for a plant that size, giving a VPD of .94, which is great for their level of maturity.
First you need your air temps up. That will automatically change your RH in the grow room, thus your VPD as well, so after it warms adequately, then start adjusting light intensity for leaf temp offset ranges ( that 2-3 degree difference), and your room RH. Make these adjustments slowly over a few days.
Don't chase leaf temps or room RH until the room temp comes up, as it's a moving target as the temps are increasing.
Leaf temps will naturally fluctuate a lot from lights on until about 10 hours into the day.
At around the 10 hour mark after lights on is when you want to take your readings that you will use for adjustments. Don't make adjustments early in the day. You want to make adjustments to cater to when the plant is working hardest, pushing it's limits.
Warm that room and things should really come around, then let them dry down for a couple waterings until you stabilize your atmosphere and get used to their new watering needs, and then find the sweet spot on pot moisture levels to stabilize the whole process.
The 3 really droopy clones also look like the myco didn't take, so to be sure, if they were mine, they would get a myco root drench mixed as per the myco instructions. In a week that myco drench should be having an effect. Drench them all if you like, it won't hurt, but warm the air to dry the plants down a bit 1st.
The one plant on the left is doing fine, so I would suspect it is heavily Indica leaning, as indicas can handle cooler temps better. It may also have a healthier mycellium in the pot.
Add heat, then go from there.
Sometimes trying to stabilize room temps will drive you nuts. If you can't get it to stabilize, try using a heating mat under your pots to warm them a bit. I usually set mine for 76F if I need them. Warming all that dirt creates a good stable heat sync in the room. It stops fluctuations AND increases microbe/fungii populations.
They will be ripping in no time
.- Thread starter
- #934
Fudo Myoo
Well-Known Member
Thanks, I’ve been dying to try them.
- Thread starter
- #935
Fudo Myoo
Well-Known Member
We’ll see what this does. I’ll check on it when I get home tonight. It’s set to about 50%. Should be worth a few degrees. I don’t want to set it too high until I’m there to watch it.Mornin' Fudo.
Here is a pic of your leaves on a couple of your plants. Look closely at the ones I circled.
See the mottling effect of lighter/darker green in the circles? A blotchy look? That is an indiicator that your plant is too cold.
Water isn't transpiring properly, it's too slow. That's why they have that over watered droop to the leaves. They may not actually be overwatered by you, but if they take in more water than they can exhale, they get droopy. Slow moving water means slow moving food as well.
If you can get your room temps up to 78 and adjust your light intensity to get your leaves to 75 or 76, 2 or 3 degrees less than air temps, with an RH of 65%, Your issues should resolve themselves in about 48 hours.
Once they start to transpire better, the effect will snowball in your favor as the water comes out of the plant.
Warm air has the ability to hold more moisture (it's dryer) than cool air, it's why clothes dryers use warm air, and water always flows from wet to dry, so warmer drier air will attract moisture faster.
The moisture in your pot is attracted to that drier air, and the dry air will suck on the plant's stomata like a straw, drawing the water in your pot thru the roots (laden with soil nutes) and into the plant, thru the plant's vascular system, and out the stomata in the leaves. You need to warm your air to increase that suction (VPD) to get the water moving out of those water-fat leaves.
If the air sucks too hard the plant will constrict the stomata to try to slow the process, and that works but, the stomata openings let both water out, and CO2 in, so too dry of air will suck too hard, constricting stomata, and CO2 intake gets restricted.
So it's a balancing act. In that whole process, if the leaf is 2 -3 degrees cooler than air temps, the rate of transpiration to atmosphere, which is really just evaporation moving thru your plant, is optimal if your room temps are in a good range of about 76F-80F in veg, allowing stomata to open wide for gas exchange in both directions, water out and CO2 in.
I prefer a room temp of 78F myself, with a leaf temp of 76 and 65% RH, for a plant that size, giving a VPD of .94, which is great for their level of maturity.
First you need your air temps up. That will automatically change your RH in the grow room, thus your VPD as well, so after it warms adequately, then start adjusting light intensity for leaf temp offset ranges ( that 2-3 degree difference), and your room RH. Make these adjustments slowly over a few days.
Don't chase leaf temps or room RH until the room temp comes up, as it's a moving target as the temps are increasing.
Leaf temps will naturally fluctuate a lot from lights on until about 10 hours into the day.
At around the 10 hour mark after lights on is when you want to take your readings that you will use for adjustments. Don't make adjustments early in the day. You want to make adjustments to cater to when the plant is working hardest, pushing it's limits.
Warm that room and things should really come around, then let them dry down for a couple waterings until you stabilize your atmosphere and get used to their new watering needs, and then find the sweet spot on pot moisture levels to stabilize the whole process.
The 3 really droopy clones also look like the myco didn't take, so to be sure, if they were mine, they would get a myco root drench mixed as per the myco instructions. In a week that myco drench should be having an effect. Drench them all if you like, it won't hurt, but warm the air to dry the plants down a bit 1st.
The one plant on the left is doing fine, so I would suspect it is heavily Indica leaning, as indicas can handle cooler temps better. It may also have a healthier mycellium in the pot.
Add heat, then go from there.
Sometimes trying to stabilize room temps will drive you nuts. If you can't get it to stabilize, try using a heating mat under your pots to warm them a bit. I usually set mine for 76F if I need them. Warming all that dirt creates a good stable heat sync in the room. It stops fluctuations AND increases microbe/fungii populations.
They will be ripping in no time
They’re looking a little better as they dry.
Also, you might want to hang the hygrometer around canopy height rather than reading what's coming off the soil.
It’s hard to oversell the importance of VPD. It’s what separates ugly sad plants from healthy vigorous plants. When you see grows where the plants are constantly droopy and sad looking like that, it’s almost a 100% chance the VPD is off and the room is too cold. This almost always creates knock on effects of overwatering. Fun fact, a plant that is overwatered experiences the same drought stresses that a plant that is severely underwatered does.
A hot dry room will have plants that stand up tall and vigorous but it will drain the resources from it faster than it can keep up, and you will see it begin to show nectrotic tips, flash signs of K deficiency, and other fun things.
If you’re growing synthetically, a hot dry climate isn’t as detrimental to the look of the plants, since you’re forcing them to take up nutrients any way. However their quality and final yield will be dramatically affected by it.
Understand this, cannabis is a hyper accumulator, any nutrients you throw at it, it’s going to take them up. Heavy metals, pollutants, micro grow bloom nutrients, you name it. When you force the plant to take up nutrients without any input from the plant itself, you degrade its final product. When you force the plant to take up nutrients at a speed faster than it’s meant to, it’s the equivalent of running a marathon at full speed and chugging soda every chance you get. You won’t die, but you’ll feel awful. Your plant won’t die, but it’s going to be awful compared to what it could be.
If you can get your grow to 78F and 65rh you’re gonna be astonished by what you see.
A hot dry room will have plants that stand up tall and vigorous but it will drain the resources from it faster than it can keep up, and you will see it begin to show nectrotic tips, flash signs of K deficiency, and other fun things.
If you’re growing synthetically, a hot dry climate isn’t as detrimental to the look of the plants, since you’re forcing them to take up nutrients any way. However their quality and final yield will be dramatically affected by it.
Understand this, cannabis is a hyper accumulator, any nutrients you throw at it, it’s going to take them up. Heavy metals, pollutants, micro grow bloom nutrients, you name it. When you force the plant to take up nutrients without any input from the plant itself, you degrade its final product. When you force the plant to take up nutrients at a speed faster than it’s meant to, it’s the equivalent of running a marathon at full speed and chugging soda every chance you get. You won’t die, but you’ll feel awful. Your plant won’t die, but it’s going to be awful compared to what it could be.
If you can get your grow to 78F and 65rh you’re gonna be astonished by what you see.
This is super important. Especially as your containers get bigger. There are all kinds of micro climates around the plants and the containers are a big source of this. You want to know what the temps are at your leaves, the roots/soil will follow suit.
The rh also varies pretty widely in my room depending on the position of my plants and the humidifiers. I want to know what the climate is where most of the photosynthesis is taking place.
- Thread starter
- #939
Fudo Myoo
Well-Known Member
Yeah I have one hanging and it’s much drier at the canopy. 40%. It’s always a struggle.
I had to get two humidifiers to be able to keep up and I just barely can keep up. I have to refill one of them every 12 hours and the other every 6.
It’s only while the weather is dry and cool though and I’m running a heater. Once it warms up it becomes infinitely easier. I’m in an uninsulated attic in a Detroit bungalow so I feel your pain lol
