How To Kill The Little White Worms In Houseplant Pots

Indoor plants can be a gorgeous way to add some personality to your home decor. Caring for them properly is key to them looking their best. One important aspect of plant care is keeping the plants free of pests, and in that regard, you may have been unfortunate enough to spot what would appear to be little white worms wriggling about in your pots. 

If you get familiar with how to kill these little white worms, you'll also be able to prevent them from coming back. The first thing you need to know is that they're not worms — they're larvae. And unlike real worms, they are definitely not benefitting your plants nor soil.

The little white worms you might find in your houseplants' soil are actually the larvae of the fungus gnat, which is a small black fly that crawls around on plant soil or flies around your plant. These larvae and flies are not only unsightly, but they also feed on the organic matter in your houseplants' soil, including their roots. A heavy infestation can cause root damage over time.

On top of this, fungus gnats can quickly spread from houseplant to houseplant. If you notice that the soil of one of your plants has small white worms in it, it is important to deal with it quickly, or you can face a full-house infestation.

To treat fungus gnat larvae in your houseplant, first remove the top layers of gnat-infested soil, which also contains the eggs of unhatched larvae. Place the soil in a bag, knot the bag and dispose of it. This may also be a good opportunity for you to fully repot your houseplant, removing the old soil and replacing it with fresh soil in a larger vessel to allow for better growth.

To remove fungus gnats from plants, you can also use ​Bacillus thuringiensis​, subsp. ​israelensis​ (Bti), a biological control. Although Bti is not effective against the adult flies, it kills the larvae. This can be applied to the soil of your affected houseplant and watered in, according to the manufacturer's directions on the product label.

Once you have removed the fungus gnat larvae from your houseplant, there are certain steps you can take to ensure they don't come back. The most important is to minimize soil moisture. Make sure you are not overwatering your houseplant and allow the soil to dry slightly between waterings.

You can use a soil moisture meter if you are unsure of how often to water. Watering your plant from below or using a mister can help you resist the urge to overwater. Using different soil covers, such as gravel or sand, can also help keep the surface of your houseplants' soil feeling drier and thus less attractive to fungus gnats.

Always check on new plants, especially their roots, before bringing them into your home to avoid bringing in new gnats. You should also fully inspect any indoor plants you are bringing back inside after a spell outdoors (during the summer, for example). A forceful spray of water around the base of the plant and top layer of soil should be enough to dislodge any new pests.