Do plants wilt with low humidity?

[AgedMaster]

Hi so im growing 3 autos and im noticing there drooping 2 hours before lights off ive had 30% humidity right from start do u think the dry air is increasing transpiration so there wilting and do u think switching from 20/4 to 18/6 would help them here she is 1 hour before lights off i will post a pic when light first turns on so u can see difference

 

[cbdhemp808]

hey @agedmaster,

Is it possible your medium is drying out at the end of 18 hours? What kind of medium are you using? Why not fill the pot with the medium?

happy growing!

 

[AgedMaster]

hey @agedmaster,

Is it possible your medium is drying out at the end of 18 hours? What kind of medium are you using? Why not fill the pot with the medium?

happy growing!

Hi pal i watered yesterday i dont think watering is the problem i think the plant cant transpire as much as much light as its taking in with the low humidity so its wilting towards lights out i think cutting a couple hours off will be a little less strain on them heres a pic 30 mins after light on all my other plants have done this but only 1 hour before light off

Im reusing coco and hydroton as media

 

[nivek]

Coco and balls. Sounds like a watering issue. Very porous, coco, requires daily watering I believe. And some p.h. adjustment as well

Karma sent friend

And as suggested, I might add some more coco to those pots

 

[AgedMaster]

Hi pal i water daily and ph every feed and coco and clay balls go well canna do a 50/50 clay ball and coco mix and i also ph'd clay balls for 24hrs and also washed and i run out of coco and clay balls or i would top pot up i have to be careful with what i bring in as there's a dome camera near my front door everything was reused from last grow i brought some coco that needed rehydrating but it was real cheap i tried on a plant i had in a cup and it wilted bad so i repotted back in cup with as much of the original coco as possible its growing fine now i was going to use that to top up i can see why bill says to use perlite or something to layer pots now canna coco pro plus does fine on its own

 

[SmokingWings]

... i watered yesterday i dont think watering is the problem ...

It certainly looks like a problem of the plant not getting enough water. Yes, if the humidity is low it will cause the plant to use more water pulled up from the grow medium the roots are in. But a plant that small should not be drooping like that at the end of the day if there was enough water available for the roots to start with.

Adjusting the lights so that there is more hours of dark is not the best solution. The light is what makes the plant grow and you will get a better & healthier plant with more light.

Speaking of adjustments. I know that you mention that you had a previous grow but it is possible that over time you lost the "watering touch" and maybe now it is time to get that touch back. I know it happens to me and I am sure it happens to others as well. I can't pick up the 2 gallon and larger pots of soil like I used to so I water by the way the plant looks and reacts and yes, even how the top 3 to 4 inches of soil feel to the touch. It should be the same for a pot of coco coir and Hydroton balls.

To get the "touch" back what I do is every 6 to 8 weeks I will pick up the pots and feel the weight. Then I water them and lift and water and lift till the weight feels like it is right once again. My lower back hates me when I do that but I get that "feeling of having the right amount of water" back into my memory without having to pick up the pots every day.

Have you been watering the coco once a day until there is some of the water coming through the bottoms of the cloth bags and into the saucers. The sauces look really clean like there has been no water run-through. A well watered medium even if the bag is not filled up to the top should last a whole day without a plant that size starting to wilt.

 

[Roy Growin]

Hello @agedmaster - Even plain coco on 12/12 will easily dry out in a day and the clay pebbles don't really hold any water and with 30% RH pretty sure that will get hot and dry super-quick
The pot is only half-filled and half of what's in there is pebbles, so that is very little coco to hold water
Pebbles obviously take up a much greater volume than perlite
That mix is really for flood n drain or drippers to keep it moist
I would let it sit in the run off so water is pulled back up as it is used up - in other words using the coco as your wick
I do it all the time, you know it's working because the surface never totally dries either

That's my opinion, hope it is food for thought

 

[AgedMaster]

It certainly looks like a problem of the plant not getting enough water. Yes, if the humidity is low it will cause the plant to use more water pulled up from the grow medium the roots are in. But a plant that small should not be drooping like that at the end of the day if there was enough water available for the roots to start with.

Adjusting the lights so that there is more hours of dark is not the best solution. The light is what makes the plant grow and you will get a better & healthier plant with more light.

Speaking of adjustments. I know that you mention that you had a previous grow but it is possible that over time you lost the "watering touch" and maybe now it is time to get that touch back. I know it happens to me and I am sure it happens to others as well. I can't pick up the 2 gallon and larger pots of soil like I used to so I water by the way the plant looks and reacts and yes, even how the top 3 to 4 inches of soil feel to the touch. It should be the same for a pot of coco coir and Hydroton balls.

To get the "touch" back what I do is every 6 to 8 weeks I will pick up the pots and feel the weight. Then I water them and lift and water and lift till the weight feels like it is right once again. My lower back hates me when I do that but I get that "feeling of having the right amount of water" back into my memory without having to pick up the pots every day.

Have you been watering the coco once a day until there is some of the water coming through the bottoms of the cloth bags and into the saucers. The sauces look really clean like there has been no water run-through. A well watered medium even if the bag is not filled up to the top should last a whole day without a plant that size starting to wilt.

Hi pal its definitely not under watered as the picture after was after first pic and i still haven't watered my coco is still moist now

 

[AgedMaster]

Hello @agedmaster - Even plain coco on 12/12 will easily dry out in a day and the clay pebbles don't really hold any water and with 30% RH pretty sure that will get hot and dry super-quick
The pot is only half-filled and half of what's in there is pebbles, so that is very little coco to hold water
Pebbles obviously take up a much greater volume than perlite
That mix is really for flood n drain or drippers to keep it moist
I would let it sit in the run off so water is pulled back up as it is used up - in other words using the coco as your wick
I do it all the time, you know it's working because the surface never totally dries either

That's my opinion, hope it is food for thought

Hi pal i tried a wick on my solo cup and it ended up overwatering i put a shoe lace through a hole in a cup i think u saw it before the leaves went puffy and stringy and coco had algae on top it wilted when i put in the cheap coco so i re potted it its growing again now

 

[Roy Growin]

Hi pal i tried a wick on my solo cup and it ended up overwatering i put a shoe lace through a hole in a cup i think u saw it before the leaves went puffy and stringy and coco had algae on top it wilted when i put in the cheap coco so i re potted it its growing again now

Fair enough - just my tuppence worth

 

[AgedMaster]

I will take another pic now of the coco and plant my mix was about 70% coco 30% hydroton there not like clay balls shape wise there like stone they where vitalink clay pebbles

 

[Delps8]

I can't provide any input re. watering (I grow in hydro) but, to your question, about 30% — that's very dry for cannabis. Your plant is in the vegetative stage and it will do best in 50% 60% humidity.

Humidity is only part of the question, though, just like it is for humans. You're right about low humidity increasing transpiration but there's also temperature to take into account. In the same way that humans feel dry air or wet air, plants do best in when temperature and humidity are in a certain range. That's the idea behind "vapor pressure deficit" ("VPD")

Plants, again like humans, are pretty much a bag of water. When it's really hot and dry, transpiration/evaporation goes up. When it's cold and damp, there's very little transpiration/evaporation. VPD is the way to figure out if a combination of temperature and humidity are "just right" for a plant.

A good source of info on VPD is this site. Poke around in the "Learn" section and you'll get smart on how you can have different combinations of temperature and RH are in a range of optimal values. Per the citations on that site, optimal VPD can increase growth by 20%±.

Your plant is also dealing with not enough light. Classic symptoms of not enough light are that the plant has limited foliage, is tall, and has a large space between the nodes ("large internodal space").

When cannabis doesn't get a lot of light, you'll end up with branches that have small, airy buds, scattered along the stem instead of large, dense colas that form when lots of light allows the buds to grow large enough that they actually grow together to form one large bud.

Fortunately, the light issue is easy to fix. Unless you have a reason not to, you might want to follow the manufacturer's guidelines. What's the make and model of your light?

 

[AgedMaster]

heres the pics now the coco is a little dry but only top layer i normally feed about now the wilt was 10 hrs after feed this is 24 hrs after feed

 

[AgedMaster]

I can't provide any input re. watering (I grow in hydro) but, to your question, about 30% — that's very dry for cannabis. Your plant is in the vegetative stage and it will do best in 50% 60% humidity.

Humidity is only part of the question, though, just like it is for humans. You're right about low humidity increasing transpiration but there's also temperature to take into account. In the same way that humans feel dry air or wet air, plants do best in when temperature and humidity are in a certain range. That's the idea behind "vapor pressure deficit" ("VPD")

Plants, again like humans, are pretty much a bag of water. When it's really hot and dry, transpiration/evaporation goes up. When it's cold and damp, there's very little transpiration/evaporation. VPD is the way to figure out if a combination of temperature and humidity are "just right" for a plant.

A good source of info on VPD is this site. Poke around in the "Learn" section and you'll get smart on how you can have different combinations of temperature and RH are in a range of optimal values. Per the citations on that site, optimal VPD can increase growth by 20%±.

Your plant is also dealing with not enough light. Classic symptoms of not enough light are that the plant has limited foliage, is tall, and has a large space between the nodes ("large internodal space").

When cannabis doesn't get a lot of light, you'll end up with branches that have small, airy buds, scattered along the stem instead of large, dense colas that form when lots of light allows the buds to grow large enough that they actually grow together to form one large bud.

Fortunately, the light issue is easy to fix. Unless you have a reason not to, you might want to follow the manufacturer's guidelines. What's the make and model of your light?

i use a 400w hps lights fine i no humidity is important but i never had a problem with it ive always grown the same way perhaps its the strain that dont like the conditions i did go town to buy a humidifier but they was sold out my plants are always tall but have plenty of nodes and always a good yield heres my king tut in a 1 gal i only fed once a day the other plant next to it was a auto on 12/12 it had about 50 nodes i had to hack a load off and tie to corner as it was taking over the hole tent it grew about ten weeks whilst flowering it was about 8 ft

 

[Delps8]

i use a 400w hps lights fine i no humidity is important but i never had a problem with it ive always grown the same way perhaps its the strain that dont like the conditions i did go town to buy a humidifier but they was sold out my plants are always tall but have plenty of nodes and always a good yield heres my king tut in a 1 gal i only fed once a day the other plant next to it was a auto on 12/12 it had about 50 nodes i had to hack a load off and tie to corner as it was taking over the hole tent it grew about ten weeks whilst flowering it was about 8 ft

If that's working for you, no need to change.

[edit]
Need a strikethrough format here on 420.

Sorry, wrong thread!

 

[Delps8]

heres the pics now the coco is a little dry but only top layer i normally feed about now the wilt was 10 hrs after feed this is 24 hrs after feed

In the bottom picture, I see splotches of light green in the leaves. That may be exaggerated by the light that you're using — it's giving the photos a yellowish cast.

What light is that, BTW?

If you take a picture under white light, it's easier to diagnose plant problems.

 

[AgedMaster]

If that's working for you, no need to change.

Hi pal the only thing i have done different is reuse coco and pebbles if underwatered it would not recover without feed i just noticed yellow on leaves im going to look now as i feed them i might up nute strength im using a dual spectrum 400w hps i dull it to 250w to get a picture cause of light on wall

 

[AgedMaster]

Its also a auto thats why im worried its 3 weeks in the other ones smaller

 

[Delps8]

Its also a auto thats why im worried its 3 weeks in the other ones smaller

HPS will tend to grow tall, lanky plants because it has a lot of red light but not a lot of blue.

"i just noticed yellow on leaves" - yeh, you'll want to deal with that. I had to "unF" an issue in my current grow that was, I think, a result of nute levels that were too low. It's easy to fix, fortunately.

 

[AgedMaster]

HPS will tend to grow tall, lanky plants because it has a lot of red light but not a lot of blue.

"i just noticed yellow on leaves" - yeh, you'll want to deal with that. I had to "unF" an issue in my current grow that was, I think, a result of nute levels that were too low. It's easy to fix, fortunately.

Hi pal i just upped my feed i also gave the smaller one same so deficiency wont show. The tap root and a few others are sticking out of pot also hopefully they take off now