White powdery stuff on clay pots?

I hope someone can answer this question. I have several plants in clay, unglazed pots - you know the cheaper ones you buy for a few dollars pretty much anywhere plants and gardening supplies are sold. Many of my plants come inside for winter after being outdoors for summer. Now I am noticing this white powdery stuff on several of these clay pots. Mostly around the top rim of the pot and the top rim of the saucer. I'm guessing this is one of those microbial varmints like fungus or mold. Does someone know what it is? How do I get rid of it? Thanks. Stacey

I would soak it in water (plant and all) and scrub it off with fingers or brush. It could also be an accumulation of salts from fertilizer depending on what it looks like.

I agree with 3jsmom, it's probably not mildew but soluable salt build up on the pots, which happens a lot with terra cotta and other pots if the soil is not flushed on a regular basis. You can remove soluable salt build up by soaking and washing the pots in a vinegar/water solution, then rinsing thoroughly and drying. Of course this method isn't possible when you have plants in them.

I would try 3jsmom's great suggestion of scrubbing the pot 's, but I would use a mild dish soap in the water and a brush. The dish soap won't harm the plants, just thoroughly flush the soil with fresh water after cleaning the pots.

OK I'll bet you're right about the salt. It seems to sort of flake off the edges of the rims. I have plants in the pots, but I have extras so I'll just sort of switch them all out and soak and scrub each pot that I've been having problems with. Thanks alot for the help! :-)

I think I would soak the plant, too. That build up is also in your soil. Just my thoughts.

it is usually salt build up and fertilizer. Take your plants out if you can. Rinse your plants by keep pouring water in the plants, distilled if you can and/or repot with new dirt.
To clean pots: first remove all dirt first using a stiff brush. Do not use soap on the planter as it may absorb the soap and transmit soap into the plant.
Spray the inside of the planter with undiluted white vinegar from a spray bottle to kill bacteria and mold. Continue to scrub briskly, then rinse the planter thoroughly with water when the inside is clean. It is often a good idea to work over a bucket and to occasionally immerse smaller pots in water.
Mix bleach and water at a ratio of one part bleach per ten parts water, then put the solution in a spray bottle. Clean stubborn stains with a small spritz of the bleach-water mixture and scrub. If possible, once clean, immerse the pot in water to neutralize the bleach as much as possible. I put the pot in water for 3 hours to soak out the vinegar and bleach. (change water around an hour or so if you can, i do this just as a precaution.lol)
to clean mineral deposits (white stains) off the outside of planters using a paste of baking soda and water. Add water to baking soda until it forms a paste-like consistency. Scrub the planter using a non-scratch scrub sponge such as a Scotch-Brite, or a loufa. Rinse well and allow all planters to dry completely.




This message was edited Dec 6, 2009 8:23 AM

This message was edited Dec 6, 2009 8:24 AM