[surfdad_grows]

It’s best practices for best results. There’s a possibility at even proper environmentals. I get weary when I can barely get my humidity below 60 and shoot for -55. I’ve got so much airflow I guess that’s why I haven’t been soo incredibly worried so far . I clear my lung room daily, I’m not running a humidifier at the moment just the humidity from the plants and I’m in a finished basement with outside access, a dehumidifier which isn’t big enough but anything helps.

[ChomeFactory]

At higher humidity the plant will take off. You won’t know you have a problem till it happens. Bud rot is most likely. It’s really disheartening when it happens.

[big_eaux]

I live where it’s 90 + humidity most of the time. I did a small experimental run last year Humidity never went below 65, with excellent airflow. The colas didn’t seem to swell like they do at that 50-55. But no issues whatsoever with any pm or mold.

Temp were 82-85.

[Royal T Farms]

I just wrote this same post this morning and I am just now seeing your post here. I have had 4 different strains harvest fine in near 70% humidity all the way to day 65. I’m having a blast seeing my plants do so well. I have had no deficiencies this far. I will keep an update.

[jmystro]

70% is asking for mold and mildew. You’re playing with fire and will eventually get burned.

[purp-terp-pheno-god]

At those levels, all it takes is a big spike and your grows done for. Like mystro said, you’re playing with fire and not in a good way lol.

[pacnw-dan]

You’re running that ragged edge of rot. The problem is in many cases you won’t see any rot until harvest, dry, cure, and then you break a big bud open and find it all brown in the middle when it “looked just fine” on the outside. While it may appear to be improving, the risks you’re running may outweigh the benefits. Certainly make sure you’ve got a lot of airflow. Any stagnant pockets will mold at 70%RH.

• This reply was modified 2 weeks ago by  pacnw-dan.

[Royal T Farms]

Thanks for all the responses. You guys and or girls are saying everything it says online and any book I’ve read, so I have to believe those that have had this issue.

[dBuds]

You’re not alone pushing high humidity, but yeah—70% in flower is rolling the dice big time. That’s veg territory. Once you’re into bloom, the rules change. Mold, mildew, botrytis, and all kinds of invisible gremlins thrive in those conditions, especially as bud mass stacks up and airflow struggles to penetrate dense canopy pockets. Just because you haven’t seen issues yet doesn’t mean you’re in the clear—you’re one stalled fan or late defoliation away from heartbreak.

Also, let’s not forget: fall outside doesn’t feel like a sauna. Mimic the seasons. Your plants aren’t trying to bulk up in late summer anymore—by flower, they’re prepping for the cold, dry finish. That’s how nature runs it, and that’s what most breeders are basing their selections on.

VPD matters more than RH alone. Flower thrives in a tighter humidity range that aligns with dropping temps and a shifting VPD. Ideal ballpark?

• Early flower: ~58–60% RH
• Mid bloom: ~50–55% RH
• Late flower: ~45–50% RH

All of that depends on gradually lowering your temps through flower like a proper seasonal shift. By late bloom, you want VPD down around 1.2 or lower. That’s when resin production ramps up, colors start to come in, and your terps lock in without risking rot.

And honestly, one of the smartest things you can do is replicate the region your breeder was cultivating in. For me, I run a lot of Humboldt Seed Co —and dialing in a late-season Humboldt hilltop climate indoors? That’s easy to mimic and always gives me results I can trust.

So yeah—high humidity is awesome in veg for explosive roots and lush growth. But in flower, you’re not growing a jungle. You’re curing the harvest. Treat it like that, and your plants will pay you back in full.

[dBuds]

Also—just gotta say, spraying essential oils during flower is a major red flag. I’ve never seen that recommended by any reputable cultivator, and honestly, that sounds like a fast track to ruining your flower. I don’t care if it’s lavender, peppermint, or unicorn tears—you should never spray anything on buds during bloom, especially past early flower.

And think about it: you’re already running high humidity, and now you’re adding extra moisture directly onto the plants? That’s basically inviting problems to come stay the night. High RH plus added surface moisture is a mold magnet, especially deep in dense colas where airflow can’t touch.

Even foliar sprays meant for IPM should be stopped once you start stacking pistils. Oils can coat trichomes, trap moisture, and absolutely trash your terpenes. It’s not helping—if anything, it’s risking quality, yield, and safety.

If you’re trying to keep pathogens away, focus on tight environmental control: airflow, defoliation, VPD, and RH. That’s how you bulletproof your flower—not by spraying your buds with essential oil salad dressing.

[Royal T Farms]

Very solid advice. I appreciate it. “Salad Dressing? Ha! That was a good one.