Humidity or not humidity issue?

[WickedMichelle]

You purchased the ac affinity humidifier correct?

Yes.

I do have it set to continuously run. I cannot get above 75% humidity without shutting off my fan. Then it gets too hot in the tent. 82.2 degrees humidity and 73.5 humidity. Fan at 25%, will not go lower.

The humidifier is set to max humidity as well

 

[SpectacularG]

Yes.

I do have it set to continuously run. I cannot get above 75% humidity without shutting off my fan. Then it gets too hot in the tent. 82.2 degrees humidity and 73.5 humidity. Fan at 25%, will not go lower.

The humidifier is set to max humidity as well

Do many different small changes to your settings and you'll eventually find a sweet spot for everything

 

[Putthataway]

Yes.

I do have it set to continuously run. I cannot get above 75% humidity without shutting off my fan. Then it gets too hot in the tent. 82.2 degrees humidity and 73.5 humidity. Fan at 25%, will not go lower.

The humidifier is set to max humidity as well

Why are you aiming for such a high humidity?

 

[WickedMichelle]

Why are you aiming for such a high humidity?

Seedlings like it I have been told. Trying to get the VPD stable as shown on the chart a few pages back.

 

[Putthataway]

Seedlings like it I have been told. Trying to get the VPD stable as shown on the chart a few pages back.

You can just put a cup over them. You are over thinking this. Set your desired humidity in the room.

 

[WickedMichelle]

You are over thinking this.

Maybe. Looking for a good first grow. Learning things at this stage helps me get better at it in the long run. Anyone can toss a seed in soil and have the plant grow. I have done this many times in the past. This time around I want to go a little more scientific about things. Temp, humidity, nutrients, light schedules. and so on and so on.

 

[SpectacularG]

You can just put a cup over them. You are over thinking this. Set your desired humidity in the room.

Thats great advice but her seedlings are past that stage, when growing in a living soil that was not sterilized its best the avoid very high humidity when not necessary during early stages too prevent undesired pathogens to affect the plant before it grows more robust

 

[Newty]

If you're trying to dial in your grow with VPD instead of just temp and humidity, you need to know the leaf temp. Leaf temp is not the same as air temp and you have to know the offset to use VPD correctly. An IR thermometer/temp gun will tell you your Leaf Temperature.
You then have to take the time to measure several leaves in several spots and calculate an average temperature, then you can calculate VPD correctly.

Also if your VPD is swinging a lot because you are trying to dial it in, this isn't good for plants and VPD should be slowly changed over a few days to prevent shock.

These reasons is why I say concentrate on the basics of temp, humidity, and dialing in your environment. Once you have complete control over your environment, controlling with VPD will be much easier.

 

[MellowRello]

Hi all.... Silly question.

I have plants in early stages. 6 days old to be precise. My tent app is calling for heavy humidity during the "seeding" phase. However the stats on my seeds say these plants like a warm dry climate. So... humidity is running in the mid 40's to the mid 50's. I have been putting a large pan of hot water in the tent to build up humidity. But should I do that if the seeds do not call for a humid environment?

Thanks in advance.

"warm dry climate" pertains to the adult plants. All sprouts need humidity because they drink through their leaves until they get enough roots to drink entirely from the soil.

 

[Ackiees]

I have the mars-hydro lights. I have been following their recommendations.

No, I do not have a humidifier. Looks like I will have to get one. Looking over the data sheet, it says short summers, not sure where I got dry climate from. I will have to see if I can find one less expensive than that.... just spent 160.00 on nutrients.

Also... no tools. Was told not to worry too much about that too much right now. 1st grow in a very long time. Very 1st for a tent and grow lights.

Soil (atm) happy frog. Will mix with ocean forest upon transplant. This is the nutrient chart I am using. Minus the Bud Ignitor and Overdrive.

View attachment 2182680

I was told to wait a bit before feeding as the happy frog has enough nutrients for a bit. At least until the plants are large enough. Should be when I transplant into a larger pot.

The FF soil nutrients alone will be good for a month tops and less time if you’re growing a heavy feeding cultivar like chem genetics.

Now I don’t think there’s anything wrong with Advanced Genetics, but they have redundant products for crazy prices and you don’t even need their entire line up because again, redundant products.

I make my own soil, start with Promix and locally collected leaf mould, let’s say 3 cu. ft….then I’ll add organic compost and worm castings to make up 20% of the soil overall mix.

Personally, I add powdered/garden lime and mix it with the entire soil batch until it reaches a very even 6.5 to 7.5 pH in the soil itself. Reason for that is research shows (Dr. Bruce Bugbee) that while common and well established knowledge tells us to keep the fee between 5.8 and 6.3 while growing in soil a lot of people have issues with micro nutrient toxicity because things like manganese are more readily taken up at lower pH levels.

Running a soil pH of at least 6.5 and potentially up to 7.5 since it will lower, put us right at the top of the spectrum for the plants to still be able to uptake iron but it absolutely negates any of the micro nutrient toxicity.

 

[Ackiees]

If you're trying to dial in your grow with VPD instead of just temp and humidity, you need to know the leaf temp. Leaf temp is not the same as air temp and you have to know the offset to use VPD correctly. An IR thermometer/temp gun will tell you your Leaf Temperature.
You then have to take the time to measure several leaves in several spots and calculate an average temperature, then you can calculate VPD correctly.

Also if your VPD is swinging a lot because you are trying to dial it in, this isn't good for plants and VPD should be slowly changed over a few days to prevent shock.

These reasons is why I say concentrate on the basics of temp, humidity, and dialing in your environment. Once you have complete control over your environment, controlling with VPD will be much easier.

This for sure…. My digital, IR, leaf reading VPD gun from AC Infinity is in the mail now and it’s only like $40

 

[Ackiees]

"warm dry climate" pertains to the adult plants. All sprouts need humidity because they drink through their leaves until they get enough roots to drink entirely from the soil.

Even a week old seedling is going to be pulling moisture in the rise zone and out of the soil but yes, they do transpire as well as absorb water and humidity with the leaves.

Maybe you’re thinking of clone cuts that HAVE to be misted regularly or otherwise kept in high humidity since the only way they can get water is from the leaves?

 

[Ackiees]

According to the chart... I am at 187. Danger Will Robinson!

I will be placing the humidifier inside the tent as another has done. All my electrical is running through the top hole I have in my tent. I have another 2 on the sides at the top however they are against a wall. Not too easy to get to.

I will have to re-set the text next grow. Tweak the set-up a little. I am glad I asked this question... I am hoping for nice tight buds. Light and fluffy are not my favorite.

I do have to take care of the pin holes. Just 3 little ones. They are near the bottom and I do see light from inside. I am not sure they are big enough to do harm in the meantime. If anything they are like 3 little stars in the night sky.

Ok... set up the humidifier.... waiting to fill the tent with moisture. I need to learn to set this properly.... figure I can control the humidity with the fan until I figure out the proper setting. I do not have the AC Infinity controller so I have to use the unit to set it up. Reads like stereo instructions LMAO ( you older folk may get that one.... ;) ). I may have to put it outside the tent if I cannot figure out how to shut the display off by 4:30 PM when it's lights out. Ok, by 10:00 ao when I have to leave for work. HAHAHA.

10 min and it seems to be working. temp 78 degrees F and humidity from 51% TO 78% Sensor is on the floor, where do you recommend I place the sensor(s)... I have the one for the fan and the one for the humidifier. The fan sensor is hanging from the top in the front corner and the humidifier is on the floor by the plants.

UG... so much to learn

I have a feeling it’s probably written about somewhere on the Internet, but my gut instinct tells me to the humidity probe as close as you can get to the center of the tent and in the canopy. The fan sensor I would place up a bit since heat rises and you want to vent that

 

[Ackiees]

If the temperature and humidity are known, VPD can be calculated--and followed. What can't be done is control the weather. Control is the difference between growing outdoors and indoors. Outdoor growers can't control the weather. Indoor growers provide the weather. What's happening outdoors can certainly be measured, though.


People also haven't always known about temperature and humidity, other than what they could feel, and VPD is calculated using temperature and humidity. They're different measurements of the same environmental phenomena. Framing an argument in terms of millennia mustn't overlook the fact that measuring temperature and humidity is also relatively new. Farmers have always had "a clue" about growing conditions, however. We all know whether it's raining or dry, hot or cold.


Of course it can. Then again, things can go wrong, too. Knowing why a grow went well or poorly can be helpful.


If humidity and temperature are measured and controlled, VPD is also measured and controlled. It just might not be calculated.

The initial investment and complexity of small tents are roughly similar to larger tents relative to scale. Cost per unit of yield probably would vary by tent size, though, due to capital cost differences.

Small tents can be challenging because they're small, but it isn't environmental control that challenges me. My main problem with my small tents is finding space for the equipment, in particular the heater and the humidifier. Placement of circulation fans can also be a problem.

What happens inside a tent certainly can be affected by other things, including what Mother Nature is doing outside. That effect can soon convince an inside grower of the value of an environment controller. It did me. Few of us can constantly adjust our tent environment when something changes, but an environment controller can do that rapidly. So, the key to precisely controlling VPD, humidity or temperature when growing in a controlled environment is to have a controller do the work. When growing in artificial conditions, we replace nature. We provide the sun, the wind, the rain, the day and the night. So, my best advice is not to try to be the controller. Sure, there's an additional cost, but I wouldn't want to run a tent without one. I just don't have the time or energy to do what a controller can do.

@HerbalEdu - I respect you as a grower and value your usually excellent advice. I just can't agree with or even understand your opinions about VPD. It's a useful tool and is easy to use (once it's understood). I grow in small tents (2x2, 2x3 & 2x4) and it's the first thing I look at when I check my controllers.

Yeah, you can grow plants without paying attention to VPD, but the overall quality of the end product is going to suffer greatly And honestly, it’s actually really easy to dial in VPD even in a small tent from my experience

 

[Ackiees]

Yes.

I do have it set to continuously run. I cannot get above 75% humidity without shutting off my fan. Then it gets too hot in the tent. 82.2 degrees humidity and 73.5 humidity. Fan at 25%, will not go lower.

The humidifier is set to max humidity as well

82. Fahrenheit is OK like as long as it doesn’t go up to 85 or above you should be fine and if there’s anyway you can add supplemental CO2, you can go into the middle of 80s and the plants will still photosynthesize because of the extra CO2 and heat.

Even for seedlings, I would suggest only running about 65% or 70% humidity

 

[WickedMichelle]

You then have to take the time to measure several leaves in several spots and calculate an average temperature, then you can calculate VPD correctly.

Well this is not what I thought LOL. I thought it was just temp and humidity. We have a temp gun, not specifically built for this but works for wax and other things.

I ran holding around 77 Degrees F and 77% humidity. Raining here right now, going to hit 80's and high humidity here. I may get to turn off the humidifier for a while today.

This for sure…. My digital, IR, leaf reading VPD gun from AC Infinity is in the mail now and it’s only like $40

I got my humidifier for that. Seems like this will 40.00 me to the poor house

Now I don’t think there’s anything wrong with Advanced Genetics, but they have redundant products for crazy prices and you don’t even need their entire line up because again, redundant products.

I make my own soil, start with Promix and locally collected leaf mould, let’s say 3 cu. ft….then I’ll add organic compost and worm castings to make up 20% of the soil overall mix.

Yes, very expensive. 160.00 For the basics. Tiny bottles that I hope will last at least one grow. As I was walking out the door I saw the gala green. Should have gone that route. As I said before... I tend to fall for hype when ignorant about a subject. I am in a 1 bedroom apartment. I can not imagine trying to make my own soil. I don't even have room for the 5 little bottles of chemicals I purchased, as well as 2 bags of soil and perlite. And the smell from the closet is horrible.

Now I noticed I have a light leak in the top of the tent where the electrical is running through. Wheeeeeeee this is fun.

 

[Newty]

I have a feeling it’s probably written about somewhere on the Internet, but my gut instinct tells me to the humidity probe as close as you can get to the center of the tent and in the canopy. The fan sensor I would place up a bit since heat rises and you want to vent that

That's how I run my Controller temp and humidity probe, in the middle of the tent, right above the canopy, and away from direct air flow from fans.

 

[WickedMichelle]

That's how I run my Controller temp and humidity probe, in the middle of the tent, right above the canopy, and away from direct air flow from fans.

I have mine hanging a little below where I would have a canopy LOL... I will move them up a little.

 

[Newty]

This for sure…. My digital, IR, leaf reading VPD gun from AC Infinity is in the mail now and it’s only like $40

Didn't even know they made one, nice find! They are out of stock online but found them for $29.99 elsewhere. Got one coming myself!

 

[Captspaulding]

don't forget you can't even follow vpd outdoor. VPD is something fairly new in the cannabis history, people have grown and enjoyed cannabis without having a clue about vpd for millenial. that being said:

cannabis can grow healthy and vigorous without you following precisely vpd, proper watering pratice and wet dry cycle are key. if your temperature is in range seedling and young plant won't care if your humidity is 20% or 70%, when in flower you will usually prefer below 50% as anything higher will potentially expose you to mold with the biggest buds depending strain and phenotypes

also controlling precisely vpd in a small tent could require a lot of effort and a lot more investement for very little gain than just dealing with the weather and the season indoor. it may depend in what room the tent is located in inside your house also.

Agree