House & garden

Home remedies for mosquitoes in the potting soil: How to drive away the fungus gnats

If a lot of small flies suddenly fly around the plants while fertilizing or watering, this is a sure sign that your flowers are infected by sciarid gnats. The small insects are annoying, but their larvae are more dangerous for the plants. Because they eat their roots and weaken them in this way. The good news: you don’t have to resort to pesticides right away. There are numerous environmentally friendly alternatives. We’ll tell you which home remedies help against mosquitoes in the potting soil.

Home remedies for mosquitoes in the potting soil: where do the fungus gnats come from?

Where do fungus gnats come from in the potting soil

The small flies are subordinate to the mosquitoes (Nematocera) and are widespread in nature. A moderately moist soil offers the best conditions for your eggs and larvae. They are therefore often found in forests and on pastures. The larvae are transparent and tiny. They live in the ground for about 7 to 10 days, where they feed on fallen leaves, bark, and fungal threads.

What do the sciarid gnats eat?

What to eat fungus gnats in potting soil home remedies

Even with careful quality control, it is not always possible to remove all eggs and larvae from agricultural products such as humus or potting soil. This way they get into greenhouses, where the soil moisture and the room temperature promote their reproduction and development. Since there is no other source of food there than the plants themselves, their roots begin to decompose.

If you put your houseplants out in the warm season, they can be attacked by the sciarid gnats. Most hobby gardeners only notice the infestation in autumn, when they bring the potted plants back into the house or apartment.

In contrast to the outdoor area, where spiders and birds catch and eat mosquitos, there are usually no natural enemies in the apartment. Therefore, they can reproduce quickly and en masse.

How dangerous are the sciarid gnats?

Sciarid gnats infest indoor plants what do

So if you buy new potting soil or young plants, there is a risk that you will also bring sciarid gnats into your home. The larvae and mosquitoes are not dangerous to humans, but young plants can die if the infestation is particularly severe.

Fighting fungus gnats in the potting soil: baking or freezing?

Sciarid gnats in the potting soil get rid of ideas

Have you bought a sack of potting soil and then noticed a swarm of small mosquitoes when you opened it? Then you should do the following:

Check the potting soil for mold or fungus. The fungus gnats prefer moist soil with a high proportion of compost and prefer to eat mushroom fibers. If you find mold or fungus, it is best to throw the potting soil away.

If the soil is only infested with mosquitoes, then you should sterilize it first and only then use it. There are two ways of doing this: you can either sterilize the soil in the oven or let it freeze outside when it is below zero.

Getting rid of fungus gnats: sterilize the potting soil in the oven

Sterilize soil and get rid of sciarid gnats

Line a baking sheet with parchment paper and spread a 1 cm thick layer of potting soil on top. Then heat them for about half an hour at 200 ° Celsius. This method will kill both the mosquitoes and the larvae. Then let the soil cool at room temperature before using it.

Fight mosquitoes in the potting soil: Freezing only works to a limited extent

Freezing mosquitoes in the potting soil won't work

The next variant is to let the potting soil freeze. Many hobby gardeners leave the sack on the balcony or terrace when the temperature is below zero. However, this method only works to a limited extent. The mosquitoes in the ground cannot survive temperatures below -16 ° Celsius, but have to be exposed to these temperatures for several days. However, since temperatures rarely fall below -10 degrees Celsius even in winter and the extreme weather does not last for days, the larvae will likely survive.

Home remedies for mosquitoes in the potting soil: What really helps against fungus gnats?

Home remedies against mosquitoes in the substrate tips

It is easy and safe to sterilize the potting soil. But what should you do if you bring home a young plant that is infected? Then the following home remedies are possible. Since most of these only kill the larvae, you should use a trap for the mosquitoes. The yellow trap is environmentally friendly and harmless to health. It attracts the sciarid gnats and they stick. Let the yellow trap work for at least a month.

Repel fungus gnats with coffee grounds

Use coffee grounds to control fungus gnats

Many hobby gardeners know coffee grounds primarily as a fertilizer. But it can also help with a sciarid gnat infestation. First place baking paper on the work surface and then spread the coffee grounds over it. Let it stand for a couple of days until it dries really well. Only then can you distribute the coffee evenly on the potting soil. A 1.5 cm thick layer will prevent the mosquitoes from laying their eggs on the substrate. An important requirement for it to work is that the coffee grounds stay dry. Therefore, only water the indoor plants from below. Fill the saucer 1.5 cm high with lukewarm tap water. The following rule of thumb applies: Avoid waterlogging at all costs. For this purpose, it is better to water the plants sparingly two to three times a week than just once extensively. So they can absorb as much water as they actually need. After 2 weeks, the fungus gnats should go away completely.

Repel mosquitoes in the potting soil with sand

Get rid of mosquitoes in the potting soil with sand

A 1.5 cm thick layer of quartz sand has a similar effect. Spread them evenly on the surface. In this case, too, the following applies: only water the plants from below, because the quartz sand should remain dry. You will get rid of the mosquitoes after a maximum of 2 weeks.

Sciarid gnats home remedies: stick matches in the ground

Fight mosquitoes in the ground with matches

Another way to kill the larvae is with matches. For a flower pot with a diameter of 20 cm you need about 4 matches. Light two of them, then blow them out. Insert all four (the two burned and the other two) upside down into the substrate. Then water the plant from above. The matches contain sulfur, which is evenly distributed through the water in the substrate. How long it takes to get rid of the fungus gnats depends on how badly your plants are infected. As a rule, the annoying flies should be completely gone after a maximum of one month.

Fight the little mosquitoes with baking soda? Better not to use this home remedy

Baking powder for repelling small flies from indoor plants

One variant that you should avoid is baking soda. It is true that the sciarid fly larvae eat it and then die. But the baking soda harms the plants and can lead to rot.

Fight fungus gnats with vinegar

Fight mosquitoes in the potting soil with vinegar

Using a home remedy, you can get an effect similar to that of a yellow trap. First fill a glass with 100 ml of water, then 50 ml of vinegar and 50 ml of washing-up liquid. Stir the detergent until it completely dissolves in the water. Then place the bowl right next to the affected plant. The smell of the vinegar attracts the pests and if they fall into the glass, they can no longer fly away.

Fight the mosquitoes in the potting soil with neem oil

Getting rid of mosquitoes in the potting soil neem oil

The neem oil is obtained from the neem tree, a wood from India. It is a scented oil that has proven itself in combating pests in the garden. Spray the potting soil liberally with the neem oil and water the plant sparingly and only from below for the next three weeks.

Repot the plants

Getting rid of mosquitoes in the ground Repot plants

The quickest way to control mosquitos in the potting soil is to repot the plants. Dig up the plant and its roots, then remove the soil completely and wash the roots under running water. Then you can plant the plants in granules of pure clay. Such clay granules are used to create hydroponics.

Getting rid of fungus gnats with nematodes

Getting rid of fungus gnats with nematodes tips

Have you used several home remedies for mosquitos in the potting soil but it didn’t work? Then you can buy nematodes. The nematodes are tiny nematodes that you cannot see with the naked eye. Among other things, the nematodes feed on the larvae of the sciarid gnats and are therefore their natural enemies. They come in a powdered clay mixture that you then add to water and stir well. Use it to water the plants from above and place them in a partially shaded place. For the next two weeks, water the flowers only from above. Make sure that the potting soil remains moderately moist. After about 20 days, you should be rid of the fungus gnats.