Question
Good Morning Darlene K. Kittle,

We have three house plants, one Kalanchoe, and two Coleus. We have two problems with them:

All three have mould on the soil. The Kalanchoe has the most mould, and is the oldest. The other two, we received about two weeks ago, and are just starting to mould.

The Kalanchoe also has tiny flies living in the soil. The adults are about one millimetre long, and look almost like miniature house flies.

The Care:

We have all three in separate pots, and are near an East facing window. The pots look large, but are really 1/2 the size. The top 1/2 has the soil, and the plant, and the bottom 1/2 is for watering. All three pots have fill holes @ the bottom, and a draw cloth, from the water base, to the soil. We don't water the soil directly.

The obvious questions are:

How do we get rid of the mould, and stop it from coming back? And how do we get rid of the flies, and stop them from coming back?

Thank you in advance Darlene K. Kittle.

Marty and Janice.

Answer
Marty & Janice,

Your mold and fungus gnats are there because of poor soil with a lot of peat moss in the soil and it is being kept too wet by the self watering pots. In my experience these pots keep most plants too wet.
Roots of plants need alternating moist and dry periods so they can breath carbon dioxide through the soil during the dry periods. Without the dry periods the roots begin to rot and attract fungus gnats.

All the peat moss in the soil makes the soil very acidic which causes it to mould when it is too wet. I reccommend that you purchase some extra perlite and some horticultural charcoal and mix these in with the soil. The charcoal will lessen the acidity and the perlite will make more air spaces in the soil so the roots will breath easier.  If it is possible I would reccommend that you at least cut the wick in half so it does not pull as much moisture up into the soil. Keeping the soil drier will get rid of the fungus gnats and the mould.

Good luck,
Darlene