Photoperiod Why is there moisture on leaves ?

[Buds Buddy]

I have been getting drops of moisture on a few leaves & I'm not sure why or what causes this. I have 2 photo plants growing. 1 plant is in a 4 x 4 x 7 tent & 1 is in a 2 x 4 x 6 tent. The plant in the larger tent is Fire OG & is way bushier. The smaller tent has a Pie Face plant. The Fire OG has not gotten any moisture at all on the leaves but the Pie Face plant does. Just about everyday since I started flowering (about 2 weeks ago) I find 1 - 3 leaves with a small drop of moisture on them. Not sure why it does this or if it's anything I need to worry about. That is why I'm looking for info on this from you pro's.
I think it has something to do with VPN / VPM ? Not sure what the letters are. All I know is it has something to do with Vapor. Tried doing a search on it but not finding any info. If it has something to do with this & you can explain or provide a link to the info I would sure appreciate it. I've never had this happen during my past 3 grows so I'm a little concerned.
Sure don't want Bud Rot. Plants are Big & Healthy looking at this time.

 

[Arthur]

not really a lot to explain, your shooting to stay in certain temp/rh areas for different life cycles of the plant.

Moisture on my leaves during mid to late flower would almost have me in a panic... moisture and buds can very easily turn into a mold rot issue.

Are you tracking your temps and humidity?

 

[Arthur]

And it's "Vapor Pressure Differential" Google that and cannabis should help you find any info your interested in.

 

[Buds Buddy]

Yes, I keep track. My temps are between 75 - 82 degrees (depending on lights on / off). Humidity stays around 25% - 28% during flower. I tied branches back this morning to try to get more air flow between the leaves to see if that will help.

 

[Buds Buddy]

Thank you for the chart & info !!!

 

[Buds Buddy]

I'll have to get a conversion chart to fully understand the chart you supplied. I'm not good with the Celcius stuff at all. U.S. so I'm just familiar with plain old Degrees.

 

[Buds Buddy]

Got the charts & found a great High Times article on it along the way. My Humidity is too low from what I'm reading. I was told by someone on another site the RH should be kept under 50% during flower but the High Times article says differently. I have a much better understanding of it now. Time to add some Humidity to my tents.
Thanks again !

 

[Arthur]

I'll have to get a conversion chart to fully understand the chart you supplied. I'm not good with the Celcius stuff at all. U.S. so I'm just familiar with plain old Degrees.

I'm not either... am on the west coast... have found it's easier to start learning C* easier to Converse with the world growers! And honestly, all the nute measurements I use are in ml as well...

Flowering can be done in relatively high RH, it requires maximum health in the plant, and a perfect environment control.

I follow the chart as best I can up until the last half of flower, then I start letting the rh run low. It's not my plant health I'm concerned with, but I don't have the control of the rest of the environment to run it tight enough to escape issues.
This was this evening, 4:58 and 5:00

 

[Mr Green Fingers]

Here is what Pulse says are ideal VPD ranges for different stages of growth, really makes sense to me.

Ideal VPD for Different Stages of Growth So now you know what VPD is, how it impacts plants, and how you can change VPD. All that’s left is to figure out how to use this information in your own grow. Ideal VPD, as a general rule for plant growth, is around 0.8 – 1.2 kPa (kilopascals). However, your plants have different needs during different stages of growth.
You need to tailor your grow environment to the stage of growth that your plants are in. Below are some general recommendations, but keep in mind that these recommendations can vary strain to strain, and setup to setup. As always, observe your plants and tweak things accordingly. Ideal VPD for Clones Clones are baby plants, they can’t handle a lot of stress because they are still just trying to form roots. Target a higher humidity and VPD closer to the lower end of the general range. The ideal VPD for clones is closer to 0.8 kPa. Ideal VPD for Vegetative Stage In veg (vegetative) stage, plants are bigger and more robust. You can reduce the humidity in your environment to increase VPD. This will increase water and nutrient uptake, but you don’t want to increase VPD too much. This will cause the stomata of the plants to close, causing them to absorb less CO2. CO2 is particularly important in the vegetative stage, because that’s the main ingredient that plants use to grow large. The ideal VPD for the vegetative stage is close to the middle of the general range, around 1.0 kPa. Ideal VPD for Flower Stage In flower stage, you the plants are robust, but the flowers are sensitive to various issues. You need to avoid excess humidity. The ideal VPD for the flower stage is closer to the top end of the range, 1.2kPa – 1.5kPa.

Link to whole article is here
https://getpulse.co/blog/vpd

 

[Slater]

I have been getting drops of moisture on a few leaves & I'm not sure why or what causes this. I have 2 photo plants growing. 1 plant is in a 4 x 4 x 7 tent & 1 is in a 2 x 4 x 6 tent. The plant in the larger tent is Fire OG & is way bushier. The smaller tent has a Pie Face plant. The Fire OG has not gotten any moisture at all on the leaves but the Pie Face plant does. Just about everyday since I started flowering (about 2 weeks ago) I find 1 - 3 leaves with a small drop of moisture on them. Not sure why it does this or if it's anything I need to worry about. That is why I'm looking for info on this from you pro's.
I think it has something to do with VPN / VPM ? Not sure what the letters are. All I know is it has something to do with Vapor. Tried doing a search on it but not finding any info. If it has something to do with this & you can explain or provide a link to the info I would sure appreciate it. I've never had this happen during my past 3 grows so I'm a little concerned.
Sure don't want Bud Rot. Plants are Big & Healthy looking at this time.

During lights off your plants will release more moister through their leaves, if any of these leave are touching the moister may collect which may form droplets... nothing to much to worry about its common and happens to most of us during light off... if not checked it may cause bud rot or PM in extreme cases (slim chance, unless you in the ball park of 80% RH)...

what is you RH lights off?

The best solution (and cheapest) is to add a fan for batter air movement, preferably an oscillating fan so it moves all the leaves as it blows over them and stop them from coming in contact with each other for long periods of time... if you find you are still getting moister and RH is above 75% (lights off) you will need to address that RH, adding heat will help loads. If you can raise the temps from lets say 19c to 24c you should see a drop in you RH by just a few % which could be the difference in getting bud rot or not (I'm a pro at bud rot, I get every year going into autumn/winter)... constant air exchange is also very important, is the air coming into the space fresh or are you just recycling the air that has been extracted? I like to control the air going in to my tent with a Dehumidifier.

unless you have the right kit and the right growing space you may as well forget about following VPD, don't get me wrong I do look at the chart once in a wile but it's more of a "Ya! i'm in the VPD range today"