Humidity and General advice

[GanjaDudeLV]

This is my first grow so really new to everything and need some advice.

20 days since flip, coco grow in 4x4 tent. Tent has 2 fans at top one oscillating and other is just blowing below the lights. 3 fans at bottom moving air around and extractor fan on full.

I'm really struggling with the humidity and sometimes its peaking 62-63%.

5 Gallon pots water 3x per day 1 liter per plant per water to get 20% runoff. Watering at lights on, 6hrs later and right before lights off. The biggest humidity peak seems to be happening at lights off.

Tent doesn't have enough room for a dehumidifier so looking for other options. My major concerns are PM and bud rot but I am a newbie and have spent the whole grow panicking over stuff that hasn't really been an issue.

Also seeing trichomes already is that normal for 20 days?

I read that diffusing essential oils can help with PM/Bud rot anyone have experience or tips on that? I only seem to find diffusers that use water which makes me think it will cause the humidity to raise even more

Thanks!!!

 

[Three Berries]

Lights off is no big deal as long as it's under 80% I would say. At least that's when I worry about it. It really depends too on the size of the plant and how much they are transpiring. My humidity will be low and then I water it will jump up 5-10% if they were dry.

 

[SBBCal]

Imo 60-63% rh is fine for 3 weeks into flower. As long as you have your inline going and enough air movement.
One thing I didn't see you mention was temp. That plays a factor in acceptable rh too. You'll want (rh) down in the mid-low 50's as you get further. You can always defoliate since your at 20days , that will drop the rh as well. (Temporary) you can try the de-huey inside the room the tents in, not inside the tent. your plants are looking great for your 1st run. Nicely done

 

[SBBCal]

I can't tell in the pics, but look into lolly- popping the lowers

 

[TintEastwood]

What they said....

Feeding 2 hours before lights out helps me with RH spiking after lights out. Coco 2 gallon fabrics.

 

[GanjaDudeLV]

Imo 60-63% rh is fine for 3 weeks into flower. As long as you have your inline going and enough air movement.
One thing I didn't see you mention was temp. That plays a factor in acceptable rh too. You'll want (rh) down in the mid-low 50's as you get further. You can always defoliate since your at 20days , that will drop the rh as well. (Temporary) you can try the de-huey inside the room the tents in, not inside the tent. your plants are looking great for your 1st run. Nicely done

Temp is around 76 during the day and 72/73 at night. The room is hooked up to AC so i can make it colder if you think that might help. Is it ok to lollypop after 20 days? I'm running feminized seeds and worried about hermies but again im a noob and could be worry over something that isnt going to cause much stress

 

[GanjaDudeLV]

What they said....

Feeding 2 hours before lights out helps me with RH spiking after lights out. Coco 2 gallon fabrics.

Thanks t I will move up my lights out watering time to help with the spike!!

 

[SBBCal]

Temp is around 76 during the day and 72/73 at night. The room is hooked up to AC so i can make it colder if you think that might help. Is it ok to lollypop after 20 days? I'm running feminized seeds and worried about hermies but again im a noob and could be worry over something that isnt going to cause much stress

Most defol before flip and at 21 day mark. I wouldn't worry about herms w/ defol. That's more environmental imo.
with your temps on the low side, that rh is acting higher than its reading. Look into VPD. Vapor pressure deficit , here's one I use.

VPD Chart

Vapor pressure deficit (VPD) chart & calculator for horticulture in controlled environment. Cannabis, tomatoes, leafy greens, cucumber.

vpdchart.com

- if you raise temps to 79-81 (if using led, 81 is good) the RH will drop on its own. If you lower temps more the rh will rise faster and easier. I'd look into controlling the temp/rh for the room , then you'll see a difference inside the tent. But yeah defoling now will help, and help your buds

 

[TintEastwood]

Thanks t I will move up my lights out watering time to help with the spike!!

You will still get a spike, but hopefully not as high or long.

Venting at lights out is common to help control temp/rh spiking, provided your intake air is acceptable RH. Also brings in fresh air/oxygen for the night cycle.

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[GanjaDudeLV]

Most defol before flip and at 21 day mark. I wouldn't worry about herms w/ defol. That's more environmental imo.
with your temps on the low side, that rh is acting higher than its reading. Look into VPD. Vapor pressure deficit , here's one I use.

VPD Chart

Vapor pressure deficit (VPD) chart & calculator for horticulture in controlled environment. Cannabis, tomatoes, leafy greens, cucumber.

vpdchart.com

- if you raise temps to 79-81 (if using led, 81 is good) the RH will drop on its own. If you lower temps more the rh will rise faster and easier. I'd look into controlling the temp/rh for the room , then you'll see a difference inside the tent. But yeah defoling now will help, and help your buds

wow ive done everything I can to reduce the temps in that room but what your saying is if I raise the temps to 79-81 it will improve? Im using LEDs to grow

 

[SBBCal]

They work together, kinda how RH spikes with lights off. No heat=rh rise

 

[SBBCal]

Yes if using LED , I run 80-85*/70% Veg-
78-82*/55-60% flower

 

[Coldnasty]

You should look into a dehumidifier for the room the tent is located. You won’t get the quality flower you’re looking for without solid control of your environment.

 

[GanjaDudeLV]

You should look into a dehumidifier for the room the tent is located. You won’t get the quality flower you’re looking for without solid control of your environment.

any recommendations on dehumidifiers I could use? If its in the room with the tent I think id need a fairly big one

 

[GanjaDudeLV]

Most defol before flip and at 21 day mark. I wouldn't worry about herms w/ defol. That's more environmental imo.
with your temps on the low side, that rh is acting higher than its reading. Look into VPD. Vapor pressure deficit , here's one I use.

VPD Chart

Vapor pressure deficit (VPD) chart & calculator for horticulture in controlled environment. Cannabis, tomatoes, leafy greens, cucumber.

vpdchart.com

- if you raise temps to 79-81 (if using led, 81 is good) the RH will drop on its own. If you lower temps more the rh will rise faster and easier. I'd look into controlling the temp/rh for the room , then you'll see a difference inside the tent. But yeah defoling now will help, and help your buds

This VPD chart is great to know from a plant health perspective but how do I protect against pm/ bud rot?

 

[SBBCal]

This VPD chart is great to know from a plant health perspective but how do I protect against pm/ bud rot?

Plenty of air circulation inside the tent, along with your inline fan. Sometimes your carbon filter or pre filter(fabric cover) will muck up, causing less airflow. You can wash the pre filter and you can flip the hinge on your carbon filter and use the other end . That helps on smell too.

 

[SBBCal]

Are you keeping any vents open at the bottom of the tent?? The more you open those up, more air exchange = less humidity. Just watch for light leaks during lights out

 

[GanjaDudeLV]

Are you keeping any vents open at the bottom of the tent?? The more you open those up, more air exchange = less humidity. Just watch for light leaks during lights out

I have all 3 vents open at the bottom and the extractor fan running with carbon and prefilter. Its in a room with 0 light leak anywhere everything is blacked out

So far the smell is pretty mild at what stage do they start to smell strong?

 

[SBBCal]

All Strain related

 

[GanjaDudeLV]

Spent a while looking into VPD and was confused about leaf temps. When my tent temp is at 75 I used an infrared thermometer and my leaves closest to the light was 68f is that correct? Should I be using the VPD chart based on those leaf temps or have I got this wrong somewhere?