Ask Anna: December Questions 2024

Happy December! Hope everyone has a great holiday season!

This month, we have the question: “Can I spray hydrogen peroxide to get rid of gnats on my orchids?”

Gnats can be recognized by their small size and the way they fly around, resembling tiny mosquitoes or fruit flies. The good news is that these pests do not harm orchids, but their presence indicates that it might be time to change the soil. By changing the soil, you will eliminate their preferred habitat for laying eggs. Decaying soil or overwatered conditions are ideal for fungus gnats.

You can use hydrogen peroxide on your orchids, but make sure not to spray it directly. Instead, create a mixture of one part hydrogen peroxide to four parts water, then mix and spray it onto the plant. You can also use this diluted solution to water the plant, which will help kill any eggs in the soil. Just be sure to water the plant only if the top couple of inches of soil are dry.

If it were my orchid, I would recommend changing the growing medium altogether and avoiding soil entirely. Orchids are epiphytes, which means they don’t need soil or potting mix; they thrive in humid and warm environments. To prevent gnats, consider repotting your orchid in Sphagnum moss or bark. It’s perfectly fine for the roots to remain above the medium.

When I water my orchids, I prefer to dunk them in lukewarm water and then drain out the excess, leaving a little water in the container. Good air circulation is also essential since fungus gnats are not strong flyers. Using a fan or spacing the orchids out on a shelf can help prevent overcrowding and keep the pests at bay.

If you have any gardening questions, send them to me at [email protected] with the subject line “Ask Anna,” and I’ll answer them in next month’s Seeker.

Stop by at 75 Cornwall Centre Road to pick up your copy of The Seeker each month.