The pots of my houseplants get moldy. How can I stop this from happening?
Answers:
You may be overwatering. Use a good potting soil mix that doesn't stay terrible wet.
Other answers:
Are your pots an unglazed terra cotta clay? Repot your plants in pots baked, glazed or treated with a sealant. You may be able to apply the sealant to the pots' exteriors after plants are in them but I think that the clay need to be dry. Look at the link for a discussion on terra cotta sealing. Even a vaseline coating inside of the pot is supposed to be a good moisture deterrent!
Are your pots an unglazed terra cotta clay? Repot your plants in pots baked, glazed or treated with a sealant. You may be able to apply the sealant to the pots' exteriors after plants are in them but I think that the clay need to be dry. Look at the link for a discussion on terra cotta sealing. Even a vaseline coating inside of the pot is supposed to be a good moisture deterrent!
In addition to Shibi, a simple keeping the pot in the sunlight might stop mold formation in the future, but you have to remove what is there.