What are fungus gnats?

This tiny flying insect belongs to a few families of insects (namely the Sciaridae, also known as dark-winged fungus gnats) and does not belong to any one particular group. Their diet includes natural plant matter, compost, mulch, and fungi, all of which are essential for their survival. Almost all of these ingredients can be found outdoors, but in the right conditions, potting soil for houseplants such as your indoor herb garden can attract these pests even more so.

When present in small numbers, fungus gnats are small insects that measure approximately 1/16 to 1/8 inch in length. An adult fungus gnat is a tiny mosquito-like insect with a black head and a white or translucent body while a larva is smaller and looks like a tiny worm with a white or translucent body and a black head. There are even smaller, dormant eggs that are yellow to white in color, which could possibly be seen if you look closely at the surface of the potting mix that is affected, making fungus gnat eggs in soil easily visible.

It is important to note that fungus gnats are known to swarm around indoor gardens, so if you see this occurrence, it should be easier for you to decipher which type of gnat you have. It is very common for people to confuse fruit flies, drain flies, and fungus gnats with each other.

In order to figure out what type of insect you have, you should consider how many of them you see in your home and the places in which they are found: Flea-sized fruit flies prefer fruit and vegetables, miniscule drain flies tend to gather around sinks, and fungus gnats tend to stick to houseplants.

How do Fungus Gnats Affect Indoor Herbs?

Not only do they like outdoor herbs, but they are attracted to indoor herbs as well. Indoor pests, like fungus gnats, are especially attracted to potting mix because of its warmth and moisture. Your herb will lose a lot of essential nutrients if you allow fungus gnats to feed on root hairs, plant roots, and other plant material. 

The good news is that there are several different methods to get rid of the fungus gnats your damaging your herbs. Fungus gnats can be treated both in the home and in outdoor containers, but the methods below are aimed primarily at treating them indoors.

How to Get Rid of Fungus Gnats Effectively

If you notice that you do have a fungus gnat problem, there are 5 methods listed below on how to get rid of them.

1. Move your herbs to a different location. This seems like a simple task, but it can be very effective. Putting newly acquired herbs in quarantine can solve this problem. In the event that you find any adult gnats on the plants, keep the infected herb quarantined for at least 17 days (to ensure the entire life cycle of the gnat is completed). You can either place them outside or in their own room where they are separate from other herbs. Once your herbs are gnat-free after the 17-day quarantine, you can return your herbs back to their original location. 
2. Cover the surface of the potting medium with pebbles to prevent adults laying their eggs on the damp surface.
3. A cheap and easy option to rid your herb garden of fungus gnats is yellow sticky traps. During the day, gnats are attracted to the color yellow. So, they will fly directly into the trap and get stuck. The downside of using this method is that many gnats will get stuck in your traps after a period of time. This will not look very appealing. To keep your garden looking its best, be sure to replace the traps when needed. 
4. A method you most likely will find in your kitchen is apple-cider vinegar traps. Use shallow containers and mix equal parts apple cider vinegar and water so it’s at least 6mm (1/4”) deep and add a few drops of liquid soap. It may be easier to place the container beside the herbs or on a potting medium surface if space permits. For best results, empty and refill your container every few days. Since gnats are attracted to yellow, consider using a yellow container but any color container will do.
5. With the cut sides facing down on the potting medium surface, cut raw potatoes attract fungus gnat larvae. Infested potatoes should be thrown into the trash and disposed of after a few days in a sealed plastic bag.
6. Repot your plants fungus gnats are drawn to over watered soil. To avoid any further issues with these pests, remove the source altogether. Give your herbs a fresh start with fresh healthy soil.

Are There Herbs That Can Help to get rid of Fungus Gnats?

Yes, there are some herbs that you can incorporate in your indoor herb gardens that prevent and fight against fungus gnats. These herbs are called:

• Horsemint– A herbal plant known as horsemint or bee balm; horsemint is a popular addition to herbal remedies for gnat control. As a perennial plant, it is also known for its strong fragrance, which makes it a favorite among gardeners.
• Catnip- It has been found that catnip is a natural insect repellent. In addition, it may also repel a variety of other pests including deer and rabbits in the wild. Its main drawback is that cats love catnip, so their presence may ruin your garden. Other limitations are that the wind direction may affect its effectiveness. Sometimes the wind directs the odor elsewhere, reducing the plant’s efficiency. What most people do is grind the leaves and sprinkle them around their gardens. And in homes, catnip essential oil is sprayed around apartments to repel gnats. Apart from these limitations, catnip is very easy to grow, and its strong scent repels almost all kinds of micro pests including gnats.
• Rosemary- besides repelling other kinds of pests, rosemary is a great gnat repellent. In addition to gnats, mosquitoes, and bugs, this plant is widely recommended for its anti-infestation properties.
• Basils– plants such as basil make excellent companion plants for vegetables. Different basils have different tastes, and you just need to find the right combination for your garden. Due to its strong odor, basil acts as an effective repellent against gnats. Furthermore, it is also effective against other pests like mosquitoes and flies. 
• Butter Worts– A natural way to protect your plants from these fungus gnats is to add this plant to your garden. This plant is natural its own sticky trap. The leaves produce a mucus like substance that traps the attracted gnats. Whether the gnat is alive or dead, its tissues will be broken down by the digestive enzymes. Once dissolved, butterworts consume and absorb insects with their digestive enzymes. The broken-down tissues will then be converted into a solution containing amino acids and other elements.

How to Prevent Gnats in the Future

Since fungus gnats are attracted to warm, wet environments; As an ongoing prevention method, be careful not to overwater your houseplants since soggy soil and a full runoff saucer are just what the gnats are looking for. Let the soil dry between waterings, but only as much as the plant will tolerate; this is no reason to threaten your plant’s vitality.

In Conclusion

An indoor herb garden can be a breeding ground for fungus gnats because of the warm, moist environment. Healthy and unhealthy plants do not matter to them. They are always on the lookout for moist soil. So, to get rid of fungus gnats, repotting your herbs should be your first step if you suspect they are housing these types of gnats. The fungus gnats’ food supply is cut off by removing the infested soil, which also causes any remaining larvae to die off. In addition, you will need to trim your herbs before repotting them if they have any root rot symptoms. 

 Outside placement of the herb plant is not necessary. Using a high-quality, well-draining, no-retention potting mix can help you avoid fungus gnats in your potting soil mix. If the problem does not get under control in 10 to 14 days, use sticky traps or nematode soaks.