How does humidity affect growth?

etruthfx

etruthfx

Well-Known Member
Figured I'd post here to get more responses. My question is this: does having humidity lower during flowering allow them to grow faster as opposed to high humidity and less frequent watering? And inversely does having the dehumifier on at night help them transpire more? How does higher/lower humidity affect growth and transpiration? Currently I keep the dehumidifier at 60 during the day time in flowering. Just wondering how does humidity affect growth while the lights are on and off and if anyone has experience with this. Thanks all for your opinions. While on the topic, co2 during lights off will make no difference correct?
 
Zoonotic6988

Zoonotic6988

Member
I think the main reason for lowering the RH is to discourage mold & rot durring flowering. I keep mine at 40. It tries to rise when lights are out the worst.

No CO2 when lights out plants are not that active & durring lights on when running it you want your temps to be higher then normal 85f+
 
etruthfx

etruthfx

Well-Known Member
Zoonotic6988 said:
I think the main reason for lowering the RH is to discourage mold & rot durring flowering. I keep mine at 40. It tries to rise when lights are out the worst.

No CO2 when lights out plants are not that active & durring lights on when running it you want your temps to be higher then normal 85f+
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I'm watering every day at 60% I imagine my garden would be a Sahara at 40% I think I'm satisfied with the day time conditions. So it's normal for nighttime humidity to go up 10-20% and there's no benefit of counteracting this? For my co2 I run 100-1500ppm during day time only at 75-80f degrees and 60% humidity
 
Zoonotic6988

Zoonotic6988

Member
In flower that is high RH to be running. It will promote mold to grow inside dense buds.

I grow in hydro but my rH will go up to 60+ with lights off and pretty rapidly. Each 4x8 gets its own auto controlled dehumidifier and I hear them cycle on quite a bit with lights out.. lights on they hardly come on.

In veg you want around 50-60% like humans do :)
 
etruthfx

etruthfx

Well-Known Member
JohnDee said:
Hi etruth,
With air that's too dry...the plants stomata close to avoid moisture loss.. And too wet...you get mold. So you walk the line between slow growth from too dry and fungal issues from too much humidity.
JD
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Thank you for your response John I appreciate it. I have attached some photos of what I'm working on for viewing pleasure. Here are some Plushberrys that I flipped on Jan 10 and also some pics from the last harvest of some finished Plushberrys. And yes it's my all-time favorite strain. Condolences to the late and great creator Subcool to me he will never be forgotten.
 

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T macc

T macc

Well-Known Member
They say dryer air produces frostier plants. I'm too simple for dehumidifiers and such. Plus I cant run more electricity in this country. Would be a bust.

I constantly grow with 60-80% rh. Never had a mold problem during the grow. Have had mold over bad luck/bad decisions.15810790804272346761233087814324.jpg
 
etruthfx

etruthfx

Well-Known Member
T macc said:
They say dryer air produces frostier plants. I'm too simple for dehumidifiers and such. Plus I cant run more electricity in this country. Would be a bust.

I constantly grow with 60-80% rh. Never had a mold problem during the grow. Have had mold over bad luck/bad decisions.View attachment 4473802
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What strain is that? Looks very sativa almost like a haze. I think that does impact it a bit where I am a fan of dense buds and less leaf I know ill have to keep the humidity somewhat lower.
 
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T macc

T macc

Well-Known Member
etruthfx said:
What strain is that? Looks very sativa almost like a haze. I think that does impact it a bit where I am a fan of dense buds and less leaf I know ill have to keep the humidity somewhat lower.
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Theres 8 different strains here. 33 plants flowering in some sorta SOG ScrOG. Strains vary from deep chunk to Neville's haze; multi ind:sat ratio. It's a pollen chuck run and I needed a quick turn around
 
Clumpyoyster

Clumpyoyster

Well-Known Member
T macc said:
They say dryer air produces frostier plants. I'm too simple for dehumidifiers and such. Plus I cant run more electricity in this country. Would be a bust.

I constantly grow with 60-80% rh. Never had a mold problem during the grow. Have had mold over bad luck/bad decisions.View attachment 4473802
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How many weeks flower r u? Could probably do a defoil to allow more light to penetrate the canopy. Your growing bud at this stage not leaves
 
T macc

T macc

Well-Known Member
Day 59f of 12/12. I defoliated and pruned in week 3. I should've pruned some more. Some strains grow too much leaf when you defoliate, which is what you see there. Some responded nicely and look great, others will loose density after the all leaves have been trimmed.

I made a new batch of soil and I think it's high in in nitrogen. I vegged for 3.5 weeks from seed. Didn't expect them to get this big. I've never flowered seedlings this young till now either.
 
Clumpyoyster

Clumpyoyster

Well-Known Member
T macc said:
Day 59f of 12/12. I defoliated and pruned in week 3. I should've pruned some more. Some strains grow too much leaf when you defoliate, which is what you see there. Some responded nicely and look great, others will loose density after the all leaves have been trimmed.

I made a new batch of soil and I think it's high in in nitrogen. I vegged for 3.5 weeks from seed. Didn't expect them to get this big. I've never flowered seedlings this young till now either.
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So are you able to move those plants? Do you water stationary or are you pulling shit out?
 
T macc

T macc

Well-Known Member
Clumpyoyster said:
So are you able to move those plants? Do you water stationary or are you pulling shit out?
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Not right now. I have deep chunk coming out soon for harvest. When I get those 6 plants out, I can spread everything else out.

I have a hose connected to my laundry room spigot, so all I have to do is get under the net and push the hose to every plant. If I could do redo this, I would've done 16 plants in 2 gallon pots. I haven't grown an actual sativa in years, I forgot how much they stretch. 4 - 6 inch plants reaching 2.5 feet now in a 1 gallon
 
C

ComfortCreator

Well-Known Member
Humidity control demands a lot of good air circulation! The "safety" from too high humidity is great airflow. Not a wind tunnel, but breezy.

What I found confusing starting out is the VPD chart. Its valid. Its pretty cool actually because in the zone during veg you can tell its right. But how the heck do I follow the VPD chart and run LEDs at 84 degrees and have humidity of 70% without mold in flower?

Well..maybe with airflow and the right strain. A gent above does it, isnt the only one and if you can do that awesome. But you dont have to in flower. The plants once mature enough can handle RH lower than the ideal range. As you ask...yes they transpire more to make up for the deficit. Yes they use water faster this way. But caution as JD says, there is a range it must be in. The general rule is 40 to 50% is good for flower and above 50% is the danger zone.

In most of the natural world, humidity or water content above 50% is conducive to mold growth...it requires spores but thats not usually hard to come by! They are everywhere except a clean room.
 
T macc

T macc

Well-Known Member
ComfortCreator said:
Humidity control demands a lot of good air circulation! The "safety" from too high humidity is great airflow. Not a wind tunnel, but breezy.
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I think good airflow is a bonus in any environment. I just got an oscillating clip fan for this tent too. I come from near the coastline in California and it's not unusual to have fog at harvest time, but it's also a windy city, so we do good.
 
Clumpyoyster

Clumpyoyster

Well-Known Member
T macc said:
Not right now. I have deep chunk coming out soon for harvest. When I get those 6 plants out, I can spread everything else out.

I have a hose connected to my laundry room spigot, so all I have to do is get under the net and push the hose to every plant. If I could do redo this, I would've done 16 plants in 2 gallon pots. I haven't grown an actual sativa in years, I forgot how much they stretch. 4 - 6 inch plants reaching 2.5 feet now in a 1 gallon
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So just tap water? No ph balancing?
 
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