Three Berries
Well-Known Member
Seeing as the humidity rises when the lamps are off, you could use the heating relay to run a dehumidifier when the temps are low using a 2 relay temp controller.
There is this one too.
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Need help adjusting to LED
- Thread starter Nutty sKunK
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There is this one too.
CheGueVapo
Well-Known Member
It's normal that relative humidity rises when temperature drops due to the light going out, because it is based on measuring the temperature.
Problems occur when that drop is so high, that at some spots water condesates because they reach the dew point.
Thats why you should keep the air ventilation and circulating air-ventilation high in the late flowering, even when the lights go out. So no condensation occurs. That protects from mold.
But.... the plants can withstand high relative humidities in the dark-phase generally speaking, because they dont need to evaporate themselves anymore and close their stomatas. Thats when fungus cant enter, the doors are closed.
A relative humidity 60-70% is ok in my eyes, when the circulating and exhaust ventilating are doing their work... dont worry the night relative humidy that much, because in total g/m³ its low.... as long as it dont rises higher than 80 for example, than I would start worrying...
Heating your plants at night can have serious adverse effect... check out DIF-technique.
www.maximumyield.com
Problems occur when that drop is so high, that at some spots water condesates because they reach the dew point.
Thats why you should keep the air ventilation and circulating air-ventilation high in the late flowering, even when the lights go out. So no condensation occurs. That protects from mold.
But.... the plants can withstand high relative humidities in the dark-phase generally speaking, because they dont need to evaporate themselves anymore and close their stomatas. Thats when fungus cant enter, the doors are closed.
A relative humidity 60-70% is ok in my eyes, when the circulating and exhaust ventilating are doing their work... dont worry the night relative humidy that much, because in total g/m³ its low.... as long as it dont rises higher than 80 for example, than I would start worrying...
Heating your plants at night can have serious adverse effect... check out DIF-technique.
Goodbye from Maximum Yield
In print and online, Maximum Yield is your source for cannabis and cultivation knowledge, with informative grow articles and tips to enhance your life with mmj.
www.maximumyield.com
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PadawanWarrior
Well-Known Member
It's called RH for a reason. Relative Humidity. Relative to the temperature of the air and the moisture in the air.It's normal that relative humidity rises when temperature drops due to the light going out, because it is based on measuring the temperature.
Problems occur when that drop is so high, that at some spots water condesates because they reach the dew point.
Thats why you should keep the air ventilation and circulating air-ventilation high in the late flowering, even when the lights go out. So no condensation occurs. That protects from mold.
But.... the plants can withstand high relative humidities in the dark-phase generally speaking, because they dont need to evaporate themselves anymore and close their stomatas. Thats when fungus cant enter, the doors are closed.
A relative humidity 60-70% is ok in my eyes, when the circulating and exhaust ventilating are doing their work... dont worry the night relative humidy that much, because in total g/m³ its low.... as long as it dont rises higher than 80 for example, than I would start worrying...
Heating your plants at night can have serious adverse effect... check out DIF-technique.
Goodbye from Maximum Yield
In print and online, Maximum Yield is your source for cannabis and cultivation knowledge, with informative grow articles and tips to enhance your life with mmj.
How Does Relative Humidity Affect How I Feel Outside?
We hear about humidity in just about every weather report on the nightly news. There are several different ways meteorologists measure humidity, but relative humidity is the most common measurement. What is relative humidity, though?
science.howstuffworks.com
Three Berries
Well-Known Member
I use some mirror film on the inside of the tent. It has a self adhesive backing but I don't use that, rather keep the paper backing on to keep some stiffness in the film. But I could not find a tape that would hold it due to condensation issues. So I just rigged my circulation fans to run 24/7. There was condensation due to the room temp vs tent temp even though the tent humidity never went over 80% (at the sensor). Might have to switch to Alien Tape.......
CheGueVapo
Well-Known Member
Right. It's just dont worry, the rH showing higher at nights. It's normal.
By heating the plants... you force them to evaporate and open stomatae.... that RISES the total humidity g/m³ for no neccesary reason and makes your plants accessible to the fungus spores.
I just meant to say stop focusing on the rH at night beeing a problem that you need to heat against.
If you have no dew point condensations, everything is alright.
I have 21°C and 68% rH often in the night, while the vents are at 100%.
It depends on what the outter ambient, the weather is... sometimes its a humid day.
Thats why you want the air maxxed, get get out any excess total water, no matter the rH is high already.
Dont worry, heat only at night if the temperature is lower than 18°C... or if you exactly know what you are doing regarding DIF according what your day-temps are! Just be aware that it has an influence on the morphogenetics of your plant.
Just my 50cents opinion.
By heating the plants... you force them to evaporate and open stomatae.... that RISES the total humidity g/m³ for no neccesary reason and makes your plants accessible to the fungus spores.
I just meant to say stop focusing on the rH at night beeing a problem that you need to heat against.
If you have no dew point condensations, everything is alright.
I have 21°C and 68% rH often in the night, while the vents are at 100%.
It depends on what the outter ambient, the weather is... sometimes its a humid day.
Thats why you want the air maxxed, get get out any excess total water, no matter the rH is high already.
Dont worry, heat only at night if the temperature is lower than 18°C... or if you exactly know what you are doing regarding DIF according what your day-temps are! Just be aware that it has an influence on the morphogenetics of your plant.
Just my 50cents opinion.
Three Berries
Well-Known Member
I'm thinking too that some 24/7 wind on the plants may help strengthen the stems?
CheGueVapo
Well-Known Member
But dont ignite a storm on them when they are young, meaning keep an eye on the wind speed. Dose matters. Wind can cause burns or say "dry-outs". "Don't knock yourself out!"
www.growweedeasy.com
"Viel hilft viel"
btw. it can rip-off the ripe lose pistils of your buds and blow them away... hopefully landing on another bud.
How to Identify Cannabis Wind Burn (Clawed Leaves) & Prevention
Exposure to too much breeze from the fan can affect the cannabis leaves to start to curl and "claw." Learn about wind burn and how to prevent it.
www.growweedeasy.com
btw. it can rip-off the ripe lose pistils of your buds and blow them away... hopefully landing on another bud.
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LeastExpectedGrower
Well-Known Member
It will. I've been using this trick for many years now (long before I decided to grow cannabis) when I was germinating and starting things like tomato plants, etc. It definitely thickens the stems and gives more fiber/structure in pretty much all plants I've used this on. Not super heavy/high speed fan, but think gentle breezes.
So on the RH/Temps... Temps rise, RH drops, Temps drop RH rises. That's why it's all relative. I'm using LEDs with not only an exhaust fan but also an intake. Though I have a somewhat smart controller (the digital unit that comes with the Cloudline T6), I'm not using the temp/RH sensor triggers.
It's just easier to run the fans full time once you've sorted where your balance point is. My swing is about 8f degrees between lights on and off. The correlating RH swing is give or take 6 points. If I want to reduce the RH at night, I turn my fans up a bit which clears moisture in the room faster and lowers the overall RH, though temps won't differ greatly from what's outside the tent. I am about to add more light though, which I think overall will be good. Right now the tent is averaging 77 during lights on and 69 at lights out. So my end goal will really be to have tent ambient temperatures around 80-83 during lights on.
CheGueVapo
Well-Known Member
Thats why sometimes it can be very useful to have an eye on the total water (g/m³) both inlet and outlet air.
With knowing that delta, and knowing your exhaust ventilation power, you know for sure that the vapor can leave.
Lets say you have your lights on the night of the day....
outside it's 17°C at 75% rH.... thats a total of: 11,52 g/m³
now that air streams in your rooms through the windows and it heats up 21°C.... still it's 11,52g/m³... but now it's 62% rH entering your grow room.
In your grow room it heats up from the light to 25°C... down to 49% rH... and the evaportion water adds up and the total water and rH rises.
The outlet now says 26°C and 55%.... this doesn't tells you shit... just "looks fine", but doesn't tell how much water is leaving.
But now you look whats that in total: 13,39 g/m³
That minus 11,52 g/m³ from the inlet is 1,87g/m³... thats the water that leaves your grow room every 1m³ .... 1,87g
Now lets say you have 300m³/h exhaust vent... that means 561grams or milliliters of water leave the Groom per hour.
Thats 6,7 liters evaporation per light phase. That gives you an idea about the thirst of them and what the exhaust capacity needs to be in the late flowering!
If my inlet humidity goes to high... I reduce light intensity 700-800, to reduce evaporation to reduce chance of mold. I regularly turn the lights down last weeks.... while giving higher intensities of up to 1000µmol the first 8 weeks. That works good! In the final phase, if the it's a very humid day then I turn intensity even lower 500 to reduce evaporation and chances of condensation at the bud-stems.
If you not keep up the 300m³/h it goes higher. If you want it lower, then you must exhaust more/faster, controlling the VPD, but the inlet total water is limiting you, depending on what the outter conditions ambient humidity are. Thats why i pick the night... it is higher rH... but lower total, when that warms up, it is relatively dry and good for grow. Better than warm air from the day 23°C that is already at 60% rH... that is a lot of total water already. Also nights better CO² in urban regions, and it is easier to not have a high DIF, other way aroung having the light on the day, you have more DIF to the night. That stretches a lot, i see that often here, lot of stretch. No problems with hot summer days having the lights on nights, too. Growing nights with the light-phase has a lot pros.
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LeastExpectedGrower
Well-Known Member
Agree. I also use Photone to help place my plants since my light doesn't have the best coverage right now. use it to scope out the best placement for the plants to get the most even PPFD across their canopies as well as a fairly accurate DLI for the plants at canopy level.
Nutty sKunK
Well-Known Member
I do have it. They are sleeping right now but will get some readings tomorrow.
Just didn’t know how accurate it would be. My phone is new so should be reliable as possible on that front.
V256.420
Well-Known Member
Do they have anything for a Samsung?
Nutty sKunK
Well-Known Member
What ppfd/dli do you aim for?
LeastExpectedGrower
Well-Known Member
PPFD that you aim for changes based upon how long your light schedule is. I'm right now generally looking for a good average of low 40's for DLI, so that means the tops of the plants may be ~47 but the bulk of the plant is closer to 40DLI while in mid-flower.
If you're comfy with Photone, they have a decent DLI calculator on their website. https://growlightmeter.com/calculator/
Pick the week, set your lighting schedule then you can start punching in PPFD numbers and see how that works out in DLI and how far on or off you are. It's a bit easier to play with than the app for DLI since the app doesn't really tell you how to optimize.
Nutty sKunK
Well-Known Member
Cheers man!
Lenin1917
Well-Known Member
Yeah, it’s just not very accurate
Milky Weed
Well-Known Member
I used an app that requires you to make a diffuser for your phone camera, just a piece of specific printer paper. I would trust apps that need a diffuser abit more than without.
But for peace of mind I picked up a $25 led light meter from dr.meter
But for peace of mind I picked up a $25 led light meter from dr.meter
LeastExpectedGrower
Well-Known Member
Luckily the photone need for the diffuser is for 20# white paper, which is the bulk of standard copier/printer paper in the world these days, and my burgeoning side hustle in lifting whiteout, paperclips and printer paper is dovetailing very well with the growing side hustle (personal use only).