help with mold growing on clay pots
 

ok guys, I need some help.

Let me start with explaining what I am trying to emulate. I have one small phal in the bathroom, it is in a clear plastic pot, which I slipped into a clay pot mainly for decorative purposes. I shower in there every night, so obviously the humidity is high. Every time I slip out the plastic pot there are condensation dropplets between it and the clay, so the clay is absorbing water when I shower then releasing it keeping the humidity around the plant high. This is my healthiest plant i have had it over a year, never had any mold or fungal or any other problems.

So recently I got several more phals and wanted to try and emulate the same growing conditions, but I can't fit them all in the bathroom, so I repotted into bark (they were in sphag) put the plastic pot into a clay pot, and instead of the bathroom, put the clay pots in/over humidity trays. The plasic pots do not go to the bottom of the clay ones, so the bottom of the clay is resting in the water slightly, allowing the pot to wick water up and then let it evaporate.

Well I must be getting alot of humidity because yesterday I noticed white/grayish fuzzy mold growing on the outside of the clay pots! It is not in the medium or on the plants that I can tell, just the outside of the clay pots.

Anyone ever had this before? Anyone have any idea how to get rid of it or keep it from developing? Can I put something in the water in the humidy trays that the pot will also absorb? I have heard people mention listerine and cinnamon for mold before. Any idea or advice is appreciated.

I am not an expert and don't grow with your conditions .. Just my thoughts; I would think that the clay is getting too moist and staying too wet so you have mould growing? Try adding some ventilation (open a window if poss?) add a fan?? sorry I can't be more helpful- hopefully someone that's has experienced this will tell you more.
Also I know hard water & fertilizer build up will show up "white" on clay pots? what water so you use?

You can also add Physan 20 to the water which inhibits the growth of "stuff"

I'd second the Physan. Dunking in brown Listerine can help too.

More air movement will also help with more than just mold. You can get a cheap clip-on one from Walmart to put on the shelf or table yours are on.

One other possibility is that it is not mold but is a salt build up. Some clays have soluable salts in them. As the water migrates up the pot it will move the salt with it and leave it behind on the surface as it evaporates. I like to soak my clay pots through several changes of water before use to minimise this.

Hello all, thank you for the reply's. It is not salt build up, because it is soft and fuzzy and smelled, and in one or two pots it migrated into the bark a little bit. However, for the most part I seem to have it beat. I gave up on the humidity trys for now, I still have them in clay pots, but that is all. It was making my entire house feel and smell like a swamp, not fun. I took off the clay pots and scrubbed them with physan and treated the plants with a beneficial bacteria organic biofungacide. I plan to instead of using the humidity trays, wet the pots well at each watering and possibly mist them mid week, we will se how long it takes them to dry. Oh, I also put some smal weak fans to move around the air, stgnant air just helps the mold. But they are not strong enough to blow around the plants.