Gnats in Plants [How to Kill Them]

Gnats in Plants [How to Kill Them]

Fungus gnats are a common problem in household plants, often resembling tiny flies hovering around the soil. These pests thrive in moist environments and can be a nuisance for indoor gardeners. To combat fungus gnats, allowing the soil to dry out between waterings is essential, as this reduces the moisture that these gnats need to breed. Additionally, sticky traps can effectively capture adult gnats, reducing their population. For a more aggressive approach, treating the soil with insecticides or natural solutions like neem oil can kill both larvae and adults, providing a comprehensive solution to this pesky problem.

What’s Fungus Gnats?

Fungus gnats are tiny bugs that flutter around indoor plants. They usually appear whenever you water your plants. These are small flies, measuring about 1/8-inch long. They are attracted to moist potting soil and decaying leaves on the soil surface surrounding your plants. On close inspection, they look like tiny mosquitoes but do not bite. While they don’t cause much harm to plants, they can be irritating to have around. Fortunately, there are ways to make your plants less appealing to fungus gnats so that they don’t appear in the first place. And if they have already infested your plants, there are methods you can try to get rid of them.

yellow sticky paper stuck with fungus gnats in house plant

Where do they hide?

Fungus gnats are tiny insects that lay their eggs in damp potting soil. The eggs eventually hatch into larvae, which feed on fungi living in the soil and sometimes even on organic matter or plant roots. The larvae are about 1/4-inch long and have a shiny black head with a whiteish transparent elongated body. If you notice a slime trail that resembles traces of slugs or snails across the top of the soil, it might be a telltale sign of fungus gnats in your plants. Fungus gnats also love light, so if you have houseplants nearby, you may notice them hovering around your windows.

Taking Actions

Take action as soon as you spot gnats in plants around your home. While it may be tempting to spray the adult fungus gnats, that’s usually just a short-term fix because more adults will appear from the larvae in the soil. A better approach is to target the larval stage of their life cycle.

Because gnats lay their eggs in the moist soil around houseplants, reducing excess moisture is critical to eliminating them. Avoid overwatering your houseplants, and make sure they have good drainage. Allow the soil to dry between regular watering, not to the point that your plant begins wilting but enough that the soil isn’t always moist. The eggs and larvae usually die in dry soil. Remember to drain any excess water that accumulates in saucers, too.

Alternative Methods

If drying out the soil doesn’t help, use BioCare Gnat Stix Traps ($7, Amazon). These sticky yellow traps can be placed near your plants to trap the adult fungus gnats and reduce the number of eggs they lay. Place a piece of damp paper near the plants to avoid touching the plant leaves with the trap. Check the traps every few days and replace them with new ones when they become covered with gnats. Eventually, these traps will eliminate all the gnats.

Fungus gnats are usually more noticeable in the fall. Some might hitchhike on houseplants when you bring them inside for the winter. Before taking plants inside, check them to ensure they’re insect-free. When you’re looking to buy new plants, examine them to ensure no insect infestations. Always use the fresh potting mix when planting or repotting.

Most Popular Flowers & Plants in the USA

RegionPopular FlowersPopular Plants
Northeast (e.g., New York, Massachusetts)Rose, Purple Lilac, Mountain LaurelSugar Maple, American Elm, White Pine
Southeast (e.g., Florida, Georgia)Orange Blossom, Cherokee Rose, Southern MagnoliaLive Oak, Spanish Moss, Saw Palmetto
Midwest (e.g., Ohio, Illinois)Carnation, Violet, Purple ConeflowerBur Oak, Prairie Grasses, Wild Bergamot
Southwest (e.g., Texas, Arizona)Bluebonnet, Saguaro Cactus Flower, Indian PaintbrushJoshua Tree, Agave, Mesquite
West (e.g., California, Washington)California Poppy, Coast Rhododendron, BitterrootGiant Sequoia, Redwood, Manzanita
Rocky Mountain (e.g., Colorado, Montana)Rocky Mountain Columbine, Bitterroot, Indian PaintbrushBlue Spruce, Aspen, Sagebrush
Great Plains (e.g., Kansas, Nebraska)Sunflower, Goldenrod, Purple ConeflowerCottonwood, Bluestem Grasses, Buffalo Grass
Pacific Northwest (e.g., Oregon, Alaska)Oregon Grape, Forget-me-not, Pacific RhododendronDouglas Fir, Western Hemlock, Ferns

This table includes the most popular flowers and plants in the USA by region, which considers a range of botanical species, including native and widely cultivated varieties.

Most Popular Flowers & Plants in Australia

RegionPopular FlowersPopular Plants
New South WalesWaratah, Bottlebrush, Flannel FlowerEucalyptus, Acacia, Banksia
VictoriaCommon Heath, Waxflower, Pink HeathMountain Ash, Silver Wattle, Victorian Blue Gum
QueenslandCooktown Orchid, Golden Penda, Umbrella Tree FlowerMoreton Bay Fig, Macadamia Nut, Queensland Bottle Tree
South AustraliaSturt's Desert Pea, Kangaroo Paw, Eucalyptus BlossomAdelaide Blue Gum, South Australian Blue Gum, Saltbush
Western AustraliaRed and Green Kangaroo Paw, Mangles Kangaroo Paw, Swan River DaisyJarrah, Marri, Karri
TasmaniaTasmanian Blue Gum, Leatherwood Flower, Tasmanian WaratahHuon Pine, Tasmanian Oak, Myrtle Beech
Northern TerritorySturt's Desert Rose, Frangipani, Desert RoseBoab, Gidgee, Spinifex
Australian Capital TerritoryRoyal Bluebell, Australian Daisy, CorreaSnow Gum, River Red Gum, Black Mountain

This table offers a basic overview of popular flowers and plants in each Australian region, focusing on a combination of state flowers, native species, and other characteristic plants. It's important to note that specific species' popularity and prevalence can vary. This table is a simplified representation. Consulting local botanical gardens or regional horticultural societies in Australia would be ideal for more detailed and accurate information.

Charlotte Gammon

By Charlotte Gammon

Meet Charlotte Gammon, our expert and author. She's our true treasure, as she has got 20+ years of experience in gardening, winery and house design. In early 2000s, she worked for magazine and was in charge of the gaardening section. Later on, Charlotte opened her own designer agency and worked as a designer and decorator. We are happy to have Charlotte with us, as she is our good friend. We value her experience and we're sure you will love the articles she created for our blog.