Mildew indoors sog grow

I know someone with a grow. Have 5 8x4 flood tables each with 99 plants in sog. Strain is indica dom so dense buds. They are having problems controlling the humidity. Their 5x5 pots are filled with hydroton. The grow rooms humidity rises at about 60-55% at about 74f. The mildew on their plants is hard to see. It's not on the leaves but inside the buds. When u look at them on the drying rack st the right angle you can see stands of pm when you pull the buds apart. The drying text 4x4 has 3 fans and a 420cfm carbon filter so airflow is not a problem. However the person has cut everything down and cleaned up the best they could but it's back again. The room is almost just big enough for the 5 tables and 10 1kw lights. It has 4 180pt dehumidifiers and a 2.5 ton ac. I told him he needs to get the humidity lower but it seems like hes having trouble doing that. He dont know what to do at this point. You can smell the dirty mildew smell when yo center the room and its driving him crazy as it ruins the quality of the product. The room has 7 oscillating fans and 4 squirrel cage fans with filters on them. Would covering the tables lower the humidty? Does anyone have any ideas? If you need more specific information. Just ask I'm sure I left somthing out.

Mold inside the buds is usually botrytis (bud rot). A greyish mold that in deeper inside the buds. Caused by flowering humidity numbers that are too high.

SDK420 said:

It has 4 180pt dehumidifiers and a 2.5 ton ac.

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Thats a lot of dehumidification for a 10kW room. How well is the room sealed up? Basically I am trying to ascertain where all the moisture is coming from. The way you describe the musty smell upon entering the room makes me think there is an issue with high ambient humidity and it's seeping into the room. How well sealed up is the room? Perhaps sealing concrete walls or floors is called for? Where do you suspect the moisture is coming from?

SDK420 said:

Would covering the tables lower the humidty?

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Covering the tables would limit evaporation indeed. Still I have run sealed 12kW rooms with uncovered tables, 6 inch pots with LECA, and did not need more than an 80 pint dehumidifier to stay below 50%, this was in Missouri, not here in Colorado where it's really dry.

If you have the room empty, no plants or wet tables... fire up the dehumidifiers, do they get the humidity down?

Also, know that as air cools the RH% goes up since the air holds less water.

Also, know that cooler air is harder for the dehumidifier to pull water out of. Think of a glass of cold water sitting in a room with warm humid air. The cool glass causes the condensation. If the glass is in a cool room it doesn't condense or very little. So if your night time temps drop you have two bad things going on, RH% spikes and the dehumidifier becomes impotent. Keep temps from dropping when the lights go off.

I'm pretty stoned sorry if I missed something. lmk if I can help more.

I also think he has a lot of dehumidifiers. He has it in a basement that is not finished. The humidity outside the room in the basement is around 55 percent. I told him to make his intake from the dry exhaust of one of his dehumidifiers. As the air was coming out about 95 degreese at 10% humidity. We are not sure where his humidity is coming from. The resivores use up about 100gallons in about 3 or 4 days in flower. His exhaust fans pull air out the the room and push it into the room next to the grow where there is 2 dehumidifiers and a small 4 inch fan that extracts the air outside the building. After a couple days on the drying racks you can pull the buds apart and see some tiny tiny strands of mildew inside the buds. He dont want to seal his growroom because he thinks it's going to use alottt of co2. I told.him the moisture from the tables is evaporating with the fans and causing too much moisture to escape and if the moisture happens to not be blown away that itl build up in the lower sections of the plants and cause mold to breakout. I havnt seen any rot from trimming his crop but I have seen the mildew and u have to look hard enough in the right place to even see it. Almost looks like a spider web stand but there's no insects on the plants or anything. Would I make sense to have any of the dehumidifiers in the grow room if he is constantly exhausting the to the room outside the grow? Wouldn't this just replace the dehumidifier air with new moister air from outside the room? Would it be a wiser idea to have all the dehumidifiers outside the room conditioning the air before its drawn in the grow through all the cracks and crevasses. His room is sealed slightly with foam board and taped. The hvac fan shuts off this the compressor to not evaporate more moisture into the room. Also since he already has mildew in a perpetual setup what is going to happen now. His previous attempts to combat the mildew did not work and he started all over again with new plants and still has mildew. Would it be better to just keep the room a steady 80-81 or 76-74 givin the situation. I think most of the air that get drawn from outside the grow ends up coming from outside the building and is around 65-35 percent humidity when it's not raining outside

Also his ac is pretty large it only take a minute maybe 2 minutes max to condition the room. Should he draw air from outside and have it go thru the dehumidifier as it comes into areas around the grow?

SDK420 said:

Would I make sense to have any of the dehumidifiers in the grow room if he is constantly exhausting the to the room outside the grow? Wouldn't this just replace the dehumidifier air with new moister air from outside the room?

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Dehumidifying the air before it enters the room will definitely help, but the sentences above is what stands out to me. Dehumidifiers need to exhaust the air outside of the space completely as in out a window. Otherwise its doing nothing since you are just making the room itself more humid and then pulling that in. I am not an expert on any of this. But tell your buddy he needs to seal his room and fix this shit asap if he is selling this herb. Especially if he is knowingly selling mildew/moldy herb with people's health at stake with respiratory issues it is straight up FUCKED UP. I feel bad if he loses money but you need to step up and tell him to stop and fix this right now or he is putting peoples lives at risk.

That's what were trying to do. The dehumidifiers drain the moisture outside the building. I mean how much co2 is it going to take to seal a room per month that's 10kw?

SDK420 said:

That's what were trying to do. The dehumidifiers drain the moisture outside the building. I mean how much co2 is it going to take to seal a room per month that's 10kw?

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Draining the water itself is good but the exhausted air from the dehumidifier still has some moisture in it or that is how I always understood it. Do your DH have exhaust lines attached directly to them? I will let someone more knowledgeable confirm this, but I would think that you need to be dumping all of your exhausted air from the room outside and not into the same space.

I have never run a sealed space with C02 so I can't comment on that. But I definitely think @Renfro was right that you may be pulling moisture in from the floor or walls especially if its an unfinished basement.

Also he was talking about somthing called sm90 but the thought of using systemic chemicals is not so great. I mean it it was a 1 time use at the beginning of flower maybe but according to other people u use sm90 every week and that shits expensive and who knows the health risks to using it. Hes been drying the product out within like 2 days to prevent the tiny amount of mildew from exploding and this also ruins quality. Hes been growing for a while but this is the first time hes dealt with the mildew

SDK420 said:

The resivores use up about 100gallons in about 3 or 4 days in flower.

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When I ran flood and drain I quantified the water used to 4 - 5 gallons per light per day. So this number isn't bad, actually less than I would expect. I would expect with 10 lights about 40 - 50 gallons per day (12/12).

SDK420 said:

Would I make sense to have any of the dehumidifiers in the grow room if he is constantly exhausting the to the room outside the grow?

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If he is exhausting then air is coming in with humidity. No point in running CO2 then either.

I get lost in the large paragraphs BTW.

He made table covers from a rool of lapscape plastic and cut holes in it to for the containers but I guess he got lazy this time and didnt use it.

We are a bit confused where we should be putting the dehumidifiers. Also there is a small fan that draws air out of the building 24/7 at a very low volume. Maybe 50cfm.

The grow room exhaust is strictly for odor control I guess. The aircooled lights dont even have fans hooked up to them he was talking about just not even using reflectors that are sealed. There are like magnum xxxl or somthing of the sorts.

SDK420 said:

Also he was talking about somthing called sm90 but the thought of using systemic chemicals is not so great. I mean it it was a 1 time use at the beginning of flower maybe but according to other people u use sm90 every week and that shits expensive and who knows the health risks to using it. Hes been drying the product out within like 2 days to prevent the tiny amount of mildew from exploding and this also ruins quality. Hes been growing for a while but this is the first time hes dealt with the mildew

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I would look at something more natural like Trifecta to deal with PM or mold if that is indeed the issue.

SDK420 said:

We are a bit confused where we should be putting the dehumidifiers. Also there is a small fan that draws air out of the building 24/7 at a very low volume. Maybe 50cfm.

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hmm. is that the only exhaust? why?

ilovereggae said:

I would look at something more natural like Trifecta to deal with PM if that is indeed the issue.

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I thought it was botrytis. Hard to comprehend the big paragraphs tho

Some pics would help us.

I think it is botrytis or some form of mildew. It's so hard to see I dont think he could get it in a picture. U almost have to look for the reflection of the strands.

There is a 700cfm fan inside the grow that exhausts the air outside into another room where there are 2 more dehumidifiers. I have looked at it with a cheap microscope and there are no signs of insects

SDK420 said:

I think it is botrytis or some form of mildew. It's so hard to see I dont think he could get it in a picture. U almost have to look for the reflection of the strands.

There is a 700cfm fan inside the grow that exhausts the air outside into another room where there are 2 more dehumidifiers. I have looked at it with a cheap microscope and there are no signs of insects

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What kind of DH are you using? The smaller 'peizo electric' units or something that has its own exhaust line?

My setup is waay smaller than yours but I do this:

AC/DH (can run in either mode) in my bedroom, and exhausting out the window. This lets me keep my room at desired temp and RH level. Then my closet intake pulls air from the bedroom. I don't have a seperate DH in here, but a way oversized AC Infinity fan with temp/RH triggers that vents outside via an exhaust port. I grow in soil though and don't have the issues that come with having a res inside my flower space.

I think you probably want at least one large DH in the basement outside the grow, and have it exhaust stale air to outside the house. Then more DH inside the grow area that also exhaust to directly outside the house.

Dri eaz-lgr. Type dehumidifier.

He sent me over a picture that turn out better than I thought.

Those pics are from a pisces that was pulled apart to see inside that gap where the strands are

SDK420 said:

Dri eaz-lgr. Type dehumidifier.

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Wow those are heavy duty. Being honest, not sure how they work. Maybe they dont need to be exhausted since they contain refrigerant?