During the winter months, when more plants are indoors, gardeners need to be on the lookout for a couple of tough pests that, once settled in, can be hard to control.
Fungus gnats, the near-microscopic flying insects that feed and breed within damp organic matter in potting soil, can actually be a problem any time of year. These tiny flying pests can spread pathogens, chew on roots and be a general nuisance. Fungus gnats’ favorite hangout is the fungus existing in moist, organic soil, so the best way to battle these bugs is by letting your houseplants dry in-between waterings. However, some overwintering houseplants-like those lovely amaryllis bulbs many of us were forcing during the holidays-like to remain somewhat moist. So…what to do?
A good drench of an indoor plant pest control product on the soil is a good start, and a layer of sand on top of the potting soil will also help. The sand helps prevent the fungus gnats from reaching and subsequently laying eggs in the potting soil, but still allows moisture to reach the roots.
On the opposite end of the spectrum, spider mites can become a terrible problem for indoor plants when conditions are too dry, which is often the case during cold days when we have the heat on. If you notice a plant’s leaves shriveling and dropping, or webbing in between stems and leaves, you’ve probably got a spider mite problem.
Again, a good pest control product will help. However, the humidity around the affected plant will need to be addressed to keep mites from returning:
- Keep plants away from the hot blast of furnace output vents.
- Spray sensitive indoor plants with water daily, if possible.
- Move all sensitive plants together and run a humidifier near them to keep air moisture levels high.