The Grow Awards 2026 🏆 
Mould on top of substrate
Dat_Maltez_Loudstarted grow question 4y ago
There is some sort of mould on the top of the substrate. I think I will spray it with diluted hydrogen peroxide.
Is this a good Idea?
likes
Dr_Drexxxanswered grow question 4y ago
Hey ! Don’t spray it ! Looks like it’s just the great white’s beneficials bacterias and fungi that shows up. You’ll be perfectly fine.
ChitownCannaChicaanswered grow question 4y ago
Trichoderma fungi—- common and it’s a sign of healthy soil! Leave it be!
1 like
Complain
PEACEMAKERanswered grow question 4y ago
Hm ml of cal mag u use? And is it organic? It can just b salt build up no need to worry but a pic would be better, good luck 👍
likes
Complain
Similar Grow Questions
Solved
nanaboham
How do I reduce humidityI have my grobox in the loft but it's got very high humidity 60-80. What's the best way to get it down to 40-50% for flowering? I already have a mini dehumidifier, 2x fans in the box. A dyson cool fan outside the box. Any tricks? Can't afford to spend mad moneyWeek 5
Other. Mold
5y ago
3
4
Solved
tiasmaaa
Mold end of flowering ?I have a small problem at the end of flowering, a little mold started to arrive, the first time I removed all the mold and I let see how it was evolving, for 1-2 days nothing came back and today there are a little again ... Should I cut everything now and hang out to dry ?Week 10
Other. Mold
4y ago
1
3
Solved
illegal_brain
Potential bud rot?My critical cure has some of the smaller leaves near and in the buds which are starting to turn rusty brown. Is this a starting sign of bud rot? Should I cut them early?
I do not see anything abnormal under the microscope or when separating the large buds by hand. Thanks!3y ago
8
4
Solved
GrowGuy97
To Treat PM or cut my losses?One of my Gorilla Zkittlez has a few small spots of PW I found last night, I removed the plant from the tent and removed all the leaves I could find that had any on it but I’m not seeing any on actual bud sights. I checked her again this morning & still don’t see anything,cut or?Other. Mold
5y ago
3
4
Solved
HierroYOlivia
Mold or what?today I found black between the florets and on the stems. mold or what?Week 5
Other. Mold
6y ago
2
2
Solved
HighRoller909
Mold on coco surface. Mycelium?Should I worry about the white mold on coco's surface? I had them before in my grows,never seen any damage caused by it but still a question in my head. humidity %60,direct air blowing to the plants,watering every other day,temps 27-28C.Other. Mold
6y ago
2
3
Solved
readzer1
Are my plants to tall and skinny for Day 28? I've been told on Reddit that my light's are prob dead by the looks of my plants (tall, with skinny stems that stretch up and they won't yield much due to this. Is there anything I can do? I have 1*800w LED , 2 X HPS 150W Bulbs
ThanksWeek 4
Other. Mold
7y ago
1
3
Solved
Dmesh
Bud rot! Should I harvest early?I wasn’t finding any mold or mildew except a few leaves until today. Had about 4days of rain and now there’s a bit of rot in every large bud it seems like. About 10 days of sun coming up now, so should I just cut the rot out and wait 1-2 weeks? Or chop now and make hash?Buds. Other
Other. Mold
2y ago
3
Solved
BoboLacetti
Funguns?! or normal? Deep Water culture + Top FeedHello, I started my first hydro dwc grow. It's a DWC with top feed (I always had that on). Is that a fungal infection on the trunk? and if so, how bad is it? what can you do? Or is that quite normal in a DWC with top feed?😱Other. Mold
Setup. Strain - Autoflowering
Feeding. Automatic systems
1y ago
1
1
Solved
Frosty_Buds
Mould on seedlingThis seed was late to spawn. Now it finally opened, even if it's quite short on the soil. I can see a fluff of mould just below the cotyledons. What should I do? Can I save it or do I risk contaminating the rest of the plants in the growbox?Other. Mold
Setup. Seedling
2y ago
4
4
Solved
Elpicor
Smartpot harmful mold?Hi guys, in the last two weeks a kind of mold has formed in the lower part of the smartpot, should I be worried? plant doesn't seem to have anything at the moment, the humidity is at 35 40% max, daily temperature max 30, min 20, do I have to flush to cleaning organic residual?Other. Mold
3y ago
3
2
Solved
ElMetitor
can 24/48 hours of darkness make mold?hello everyone, for better or for worse, the time has come for the harvest, do you think it is worthwhile to let the plants do 24 h 48 h of darkness or is she a bullshit? I have my indica for a day inside the grow with an air conditioner at 22 degrees C and a dehumidifier with 25Buds. Other
Other. Mold
5y ago
4
5
Solved
AvoidingBananas
Mouldy, webbed budsThe humidity was too high when I went away and now my buds are mouldy. Obviously I’m heart broken (mainly at my own stupidity because I should know better!) and I wondered if there was anything I can do to recover some of the crop. Can I wash? spray? Dry out…basically anything?!?Buds. Other
Other. Mold
3y ago
3
Solved
vtrock
Is the bud rot? What to do?Is this bud rot?
I found it on two bud sites so far on my big plant.
What would you do?
1) Assuming it's rot or some other infection would you just harvest now?
It's like 2-2.5 weeks early.
2) Wait one more week and see and risk spread?Week 22
Other. Mold
2y ago
2
3