Bad pot for growin pot

I have a plant 6 weeks into flower and the ceramic pot does not drain well. It is what I had that was big, and I hadn’t found this site before I potted them.

Anyway since repotting is not an option, I need advice. I noticed a fine white mold on the surface of the soil. I have done the following:

I used a miniature “rake” (back-scratcher) and removed about 1/2" of topsoil
made sure the fan was aimed directly at the dirt
aerated the dirt with a bamboo skewer.
Brushed the exposed base of the stem clean

Is there anything I should add to the surface or anything else I should do?


LOL, laughing so hard, not at your mold issues but at the backscratcher thing. I have a telescoping metal back scratcher and I use it as a little rake for the soil in my pots between watering. I don’t know about the mold thing though.


The little one with the metal hand? LOL


Neem oil spray can help. There are other fungicides on the market, with which I’m not familiar. Let the soil surface dry between watering. Sunshine is the great sanitizer. If your plant has never been in direct sun, look up “hardening off” before you throw it out there.

Good luck with it!

I don’t think I’ll be putting her out, due to the humidity and the BUGS! but I will look into the neem oil or other treatment. Would dropping a white LED close to the soil for a bit help?

Also, I am not in a 420 state. I am in a coastal area that is set for darkness Monday afternoon…

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@Whodat66 - I can’t imagine an LED would do any good, but I could be wrong. You might research UV light or something similar for it’s mold/mildew killing properties. I’ve seen some kind of UV lights in butcher shops that supposedly kill … something or other.

Another thing I would do is mix up a teaspoon or two of baking soda in water and dish soap and spray the soil and stem once. It raises the surface PH so mold can’t form. More than once and you risk raising the PH of the soil and killing your plant.

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Sounds good except for the soap, mind if I wait on a second opinion? I’m only looking at another week or two before harvest and don’t want to do anything too drastic.

Absolutely you need more opinions from the real experts here.

The soap, by the way, is very common in plant sprays. I know, it sounds strange but the soap reduces the surface tension of the water and help it distribute more evenly.

EDIT: Really, with 2 weeks to harvest you can probably keep that mold in check right to the end.

I have also added soap to a sprayer with Round-up in it so it sticks to the plants I want to kill. Initial benefit might be outweighed by unforeseen reactions. I’ll be flushing her in another week.

I seen a video on YouTube showing to wash your first trimming buds with hydrogen peroxide and water by dunking them which will cause the mold to float to the top of the water. Then just hang to dry and place fan near.

I have never had white mold on my soil or coco. Fertilizer salts create a fine white powder on the surface. The container is ok provided there are drain holes in the bottom and for your next grow add a significant amount of perlite for added drainage and aeration of the roots.You may have white mold, I have just never seen it in my grows. If you are harvesting soon - then I think your fine to finish out the grow with a flush of water. Not adding anything else.


You could mix a small amount of peroxide with some water and put it in a spray bottle and mist the soil.

But having the fan blowing on the soil should help keep it dry enough where mold shouldn’t form.

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I was thinking I read something on here several weeks ago about using skim milk and water to get rid of mold. Let me see if I can find it!

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I use an air purifier with ionizer in my grow area- they are supposed to kill mold spores as well as it doubles as a fan.


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Sounds like @jeffro might have come up with it!!
I found this though, must have been someone quoting Robert? Not sure but here it is if it turns out that your problem isn’t sale build-up. “Do you mean powdery mildew? Not sure about the M before PM? I did a search here and got this. We have some new marijuana clones that have a gray mold on them. Is there any cure for this? It looks like a spore because it is dry and puffs up when you come into contact with it. We’ve been removing any infected leaves but nothing has really altered. The mold just keeps spreading. Aside from the leaves that have been affected, the marijuana plant is growing fine. We have a dehumidifier in the room, so it’s dry in there. Is it possible to cure this or should we just start over?
I have been cloning this particular marijuana strain for a number of years. Last year some powdery mildew infected it. I thought the environment was to blame so I sprayed the clones with some natural defense methods. When the strain was introduced to a brand new environment with more plants, the mildew came back. Can powdery mildew be infused with the marijuana plants DNA or is it just an environmental issue?
Powdery mildew is definitely your problem. The fungus attacked marijuana intermittently prior to 1999, but, after that, some strains became more aggressive. It appears more commonly in both indoor and outdoor locations. The mildew has evolved in such a way that cannabis is an acceptable source of food. The problem will get worse before it gets better as industrial hemp is allowed to grow in large volumes in Canada. Many different species of powdery mildew exist, but, as far as I know, no research has indicated which ones are going after marijuana. Powdery mildew is often white in color.
In contrast to many other molds and fungi, powdery mildew works best under moderate temperatures at around the low 70’s with 50% humidity. Unfortunately, those conditions are also ideal for growing cannabis. If you get an infection of powdery mildew, don’t blame yourself. The spore just came into contact with an area that it could thrive. The spores are travel through the air and float around until they find a prime target. Based on their sheer number, they’re going to find a good location to land. Because the spores are airborne and endemic, it’s hard to keep them from attacking. When it is cold outside during the winter, there are fewer spores because of the cold and rain and the lack of spores actually growing outside.
The DNA for powdery mildew does not and cannot combine into the plants’ DNA. Eventhough some bacteria and viruses can occasionally shift DNA patterns in some organisms, fungi and molds usually don’t. The plants showed the disease because they were actually infected again. Instead of waiting for signs of re-infection, use fungicides as prophylactics. As soon as a plant is attacked by mildew, it becomes a vector for spreading that disease. All the spores grow on the surface, and removing the plant entirely just makes the spores airborne again.
There are, of course, ways to deal with and control powdery mildew. Some of the products that have proved useful for many growers will be listed here. They are labeled for use with edible vegetables and are generally thought to be non-toxic.
AQ10 is a biogfungicide that has fungus ampelomyces quisqualis. This is considered a hyperparasite fungus that works to colonize the powdery mildew infection and kill it. The Organic Materials Review Institute (OMRI) lists it for organic crop production. It is manufactured by Ecogen, Inc.
Cinnamite has many uses for eradicating pests like mites, aphids, and even powdery mildew. It is quite effective and is composed of a cinnamon extract called cinnamaldehyde. Created by Mycotech, you can find it in a number of internet venues as well as some stores.
Milk can be used in a solution of 80% water and 20% skim milk to eliminate powdery mildew. It is highly effective and can be used over and over again to ward off any further attacks.
Neem oil comes from the Indian neem tree and works as an all-natural pesticide. It can be used against mites and insects, but it also functions as an effective fungicide and tonic. The oil benefits plant health and vigor and can be found under a number of different brand names.
Plant Shield comes with the beneficial living fungus known has tichoderma harzanum (strain T-22). The fungus creates a symbiotic relationship with the cells of the plant on the surface of the leaf. It shields the leaf from any oncoming attacks and will eliminate organisms that have already colonized the plant. It will attack molds like botrytis (gray mold), pythium, powdery mildew, fusarium wilt, and rhizoctonia. These molds go after the stems, roots, and leaves of the plants. Humans and pets are not harmed by the fungus and it is labeled as organic. It is manufactured by Bioworks, Inc.
Potassium bicarbonate, an alkaline compound, shifts the microenvironment from acidic to alkaline. Most fungi and molds like environments that are acidic, and, when potassium bicarbonate is introduced, they lose their function and their organs collapse. Brand names include Armicarb 100, KaliGreen, and Remedy.
Serenade is a fermentation product that comes from the bacterium known as bacillus subfiles. It is harmless to animals and has several methods of operation. It fights off many different fungi and molds and will compete with them for resources. The plant’s immune system (system-active resistance) is activated by the presence of this bacterium. Plants also absorb Serenade and then translocate it, increasing its effectiveness. It is manufactured by AgraQuest.
Sodium bicarbonate, commonly known as baking soda, is a lot like potassium bicarbonate in the way it’s used. It should not, however, be used a number of different times because the sodium can build up and harm the plant.
You should treat the plant with one of these products every 7 to 10 days to prevent the reappearance of mold, mildew, or fungi. If the symptoms appear and the fungus begins reproducing, the treatment is less effective.”

There is a short paragraph in there about skim milk and water and another about baking soda!

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I have used milk before for powdery mildew. Its like a 1/10 ratio and it has worked with no negative side effects. If this was a hydro setup I would be looking more into something stronger like hydrogen peroxide.


Thanks for all the help. I’m hoping that it was fertilizer salt. Should have taken a pic. Either should be held in abeyance for a week or so with the removal of the topsoil. There is nothing on the plant itself (why I’m leaning towards salt) and my cleaning the stem was just to get the dirt off.


I used peroxide before to beat gnat larvae, so I know that’s safe :slight_smile: