If suddenly there are many when fertilizing or wateringsmall fliesflying around the plants, then this is a sure sign that your flowers are infested with fungus gnats. The small insects are annoying, but their larvae are more dangerous for the plants. Because they eat their roots and in this way weaken them. The good news: You don't have to resort to pesticides straight away. There are numerous environmentally friendly alternatives. We'll tell you which home remedies help against mosquitoes in the potting soil.
The little fliesare the mosquitoes(Nematocera) subordinate and widespread in nature. A moderately moist soil offers the best conditions for their eggs and larvae. They are therefore often found in forests and pastures. The larvae are transparent and tiny. They live in the soil for about 7 to 10 days, where they feed on fallen leaves, bark and fungal threads.
What do fungus gnats eat?
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 is how to get therethem in greenhouses, where soil moisture and room temperature promote their reproduction and development. Since there is no source of food other than the plants themselves, they begin to decompose their roots.
If you put your houseplants outside in the warm season, they can be attacked by fungus gnats. Most hobby gardeners only notice the infestation in the fall when they bring the potted plants back into the house or apartment.
In contrast to the outside area, where spiders and birds catch and eat mosquitoes, there are usually no natural enemies inside the apartment. Therefore, they can multiply quickly and en masse.
How dangerous are fungus gnats?
So if you buy new potting soil or young plants, there is a risk that you will also bring fungus gnats into your home. The larvae and mosquitoes are not dangerous to people, but young plants canparticularly severe infestationenter.
Fighting fungus gnats in potting soil: baking or freezing?
Have you bought a bag of potting soil and then noticed a swarm of small mosquitoes when you opened it? Then you should do the following:
Check thosePotting soil for mold or fungal infestation. Fungus gnats prefer moist soila high proportion of compostand prefer to eat mushroom fibers. If you find mold or fungus, it's best to throw away the potting soil.
If the soil is only infested with mosquitoes, then you should first sterilize it and only then use it. There are two options in this regard: you can either sterilize the soil in the oven or let it freeze outside in sub-zero temperatures.
Get rid of fungus gnats: Sterilize the potting soil in the oven
Line a baking tray with baking paper and spread a 1cm thick layer of potting soil on it. Then heat them for about half an hour at 200° Celsius. This method will kill both the mosquitoes and the larvae. Then allow the soil to cool at room temperature before using.
Fight mosquitoes in the potting soil: Freezing only works to a limited extent
The next variant is to let the potting soil freeze. Many hobby gardeners leave the bag on the balcony or terrace when temperatures are below zero. However, this method only works to a limited extent. The mosquitoes in the ground cannot survive temperatures below -16° Celsius, but must 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 are likely to survive.
Home remedies for mosquitoes in the potting soil: What really helps against fungus gnats?
It is easy and safe to sterilize potting soil. But what should you do if you bring home a young plant that is infected? Then the following home remedies come into question. Since most of them only kill the larvae, you should use a trap for the mosquitoes. The yellow trap is environmentally friendly and harmless to health. It attracts fungus gnats and they stick. Allow the yellow trap to work for at least a month.
Drive away fungus gnats with coffee grounds
Many hobby gardeners know coffee grounds primarily as a fertilizer. But it can also help with an infestation of fungus gnats. First place baking paper on the work surface and then spread the coffee grounds on it. Leave it for a few days until it dries really well. Only then can you distribute the coffee evenly over the potting soil. A 1.5cm thick layer will prevent mosquitoes from laying their eggs on the substrate. An important prerequisite for it to work is that the coffee grounds remain dry. Therefore, only water the houseplants from below. Fill the saucer 1.5 cm high with lukewarm tap water. The 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 rather than just once extensively. This means they can absorb as much water as they actually need. After 2 weeks the fungus gnats should disappear completely.
Repel mosquitoes in the potting soil with sand
A 1.5 cm thick layer of quartz sand also has a similar effect. Distribute them evenly over the surface. In this case too, the following applies: only water the plants from below, as the quartz sand should remain dry. After a maximum of 2 weeks you will get rid of the mosquitoes.
Fungus gnats home remedy: stick matches in the ground
Another method 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 and 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 fungus gnats depends on how badly infested your plants are. As a rule, the annoying flies should be completely gone after a maximum of a month.
Fight the little mosquitoes with baking soda? This home remedy better do not use
One option to avoid is baking soda. It is true that the fungus gnat larvae eat it and then die. But the baking soda harms the plants and can lead to rot.
Fight fungus gnats with vinegar
With a home remedy you can achieve a similar effect as with a yellow trap. First fill a glass with 100 ml of water, then 50 ml of vinegar and 50 ml of dish soap. Stir the dishwashing liquid until it completely dissolves in the water. Then place the bowl directly next to the affected plant. The smell of the vinegarattracts the pestsand if they fall into the glass, they can no longer fly away.
Fight mosquitoes in the potting soil with neem oil
Neem oil is obtained from the neem tree, a tree native to India. It is a fragrance oil that has been proven to combat pests in the garden. Spray the potting soil generously with the neem oil and water the plant sparingly and only from below for the next three weeks.
Repot the plants
The quickest way to get rid of mosquitoes in potting soil is to repot the plants. Dig up the plant including the roots, then remove all of the soil and wash the roots under running water. Then you can plant the plants in pure clay granules. Such clay granules are used to create hydroponics.
Get rid of fungus gnats with nematodes
Have you already used several home remedies for mosquitoes in the potting soil but it didn't work? Then you can buy nematodes. The nematodes are tiny roundworms that you cannot see with the naked eye. The nematodes feed, among other things, on the larvae of fungus gnats and are therefore their natural enemies. They come in a powdered clay mix which you then need to add to water and mix well. 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 the potting soil remains moderately moist. After about 20 days you should be rid of the fungus gnats.