I’m growing in a enclosed room in the basement with mostly sheetrock walls. In the past there was a bit of flooding during the spring. It’s been a few years since it happened, and the problem is fixed, but I’m wondering about black mold in the walls. It has somewhat high humidity as well so I’m guessing if it was there, it has stayed there.
Any advice to try to get rid of it? I was thinking to used some diluted bleach and basically let it penetrate the walls at the bottom where the water entered. Crazy idea? I should also mention that my plants will be close to the wall. I am elevating the floor with pallets with plywood on top to keep them off the cement so they won’t be up against any walls, but in close proximity.
Thank you everyone for your help so far. I really appreciate it
Start a major de-humidify program.
Consider relocating or seeking professional helpBEFORE tent and grow.
Ventilation Exhausting tents as well as basement presents smell and costs.
TOO SERIOUS an environment and too serious a health issue can result without correction, intervention and proper maintenance. Sorry but Russian Roulette with five filled chambers in the cylnder, not promissing odds. Good news "we can fix it, with MORE something…
Elevating tent on 2 inch pink insulation board will also help, maybe. I did mine, but only above the concrete (no pallets for trip hazzard). Previous insulating lung room Garage helped, but most important factor, I missed reading in above, WHAT HEIGHT CEILINGS and tent available?
At 8 ft I would build my own rooom (and may yet still, for 2023 after disney.
From what I’ve been reading you want a high humidity when growing. I’ve had dehumidifiers down there for years. Other than ripping out the sheetrock what would be the alternatives without hiring a professional?
Thanks for the reply.
They aren’t going to be in tents. It’s an open room in the basement.
I run 40-50% RH tents for all stages of lights on.
I try not to water before 38%.
Dehumidify should prevent mold, but I spill so much water I need good drainage.
HGTV Says FIX IT RIGHT
Rip out the sheet rock and remove damaged, remediate remaining and re-build correctly with needed improvements (My 1959 house had no insulation. Now, it has vapor barrier, no mold, insullation and sound proofing, with new 5/8 drywall, painted PLENTY. All air leaks sealed, but we open windows).
See, I’m finding more information about how to raise humidity than lower it. I’m going to get a humidity thingamajig to put in the room. You say 40-50 percent is where I want to be?
Thanks for the help.
Its where I want to be. Not, necessarilly you.
I control the ventilation with AC-I Cloudline controllers. Bluetooth support 20 feet distance. WiFi further.
I can raise humidity with watering, spilling, or WICKING. Dehumid is the harder to control sometimes.
Currently, my management plan makes these useless (open windows for cooling).
However I have had one Frid running 5 years continously (MCAS IWAKUNI) and 2 years since (Wife’s gentle dryer). Available for lung room or DRY tent. gallons dumping are a pain, but thats life.
Spray with bleach solution then KILZ over it after dry
AND make sure to handle PPE. Problem Prevention Equipment (breathing, clothes) or Personal Protective Equipment, your choice.
Youre right they want high humidity, compared to what our noses throats and our homes want.
I lived in a rotten place. I feel horrible because I blame it for my (gone) cat’s raspy breathing. I got outta there ten years ago and don’t wish it on anybody. Get air venting out of that basement steady to the outside, now if not already done, growing or not. Move if you can. 
protect yourself live long enjoy every breath 
IMHO as long as your plants don’t actively have mold growing on them or in your flowers what’s in your walls won’t affect them. A dehumidifier down there will help keep your rh down. A fan to keep the air moving in and beneath the canopy will help reduce the chance for PWM also. What is your rh down there typically?
Thats what I would do, dehumidify that place down to 35% then do the wash, and paint… Several coats
AC-Infinity has my money with minimal complaining. The ability to control and move air from distance is ffantastic. 1970-80 grow usually succombed to heat. Cloudline Controllers have software I utilized for garden protection while sleeping, All sorts of paramenters and conditions monitored, effortlessly, somewhat. good luck and good growing!
If the space has nothing growing in it you could try an ozone generator for killing mold and mildew (and most anything else in the space so follow directions).
I’m a mason by trade. And I deal with mold in concrete and block all the time. So my suggestion would be to take down the sheetrock on all the walls. Spray bleach on all of them. Then on any concrete walls go to the home Depot and get a gallon of drylock it’s white paint meant to waterproof block and concrete walls. Paint everything even the floor if it’s concrete. And get a good vent to vent out all the humidity. Start with new sheetrock and insulate any wood framed walls!!!
Available at Lowes. Will make the treated surface hostile to future mold growth.
I would clean it up with soapy bleach water first then treat it.
Black mold will release a gas that will make you sick when you kill it. Bleach, Kilz, Zinsser Bullseye or whatever you kill it with will release this gas. Wear a respirator when you do it. I have treated a lot of this when I was renovating hotels. Every corridor wall was covered with black mold under the vinyl wall covering. This is because the bath/showers are always just inside the doors. Anyway, this wet and forget will keep the mold from returning. I treat my house siding with it. Should work for several years inside.
