12 Tips To Keep Unwanted Insects Out Of Compost

Last updated on October 21st, 2023 at 10:26 pm

In the garden, we love compost! It is a recycling technique that helps us to reduce our waste easily. Thanks to it, the garbage cans are almost empty since all the organic waste is thrown in the compost. We then benefit from a natural and 100% ecological fertilizer, ideal to cultivate plants and vegetable garden. But you have to be careful, not all waste can be put in the compost and you have to respect some rules, especially if you don’t want to attract flies, gnats and other undesirable insects.

Insects in my compost: where do they come from?

Since compost is an organic element of the garden, it can host different types of insects. They are real indicators of the state of the compost. Contrary to popular belief, they can be a sign of a healthy compost. The appearance of keton larvae or manure worms indicates that the compost is ready to be installed in the garden. These worms absorb the harmful organic elements, digest them, and reject them into healthier material. Where flies and gnats only feed and develop by laying eggs. These eggs then warn you of the malfunctioning of your compost.
All these small animals are attracted by peelings or overripe fruits left in the open. The midges proliferate rapidly and can become a nuisance in your daily life. Be aware that their larvae develop under favorable temperature and humidity conditions. Certain starchy foods are also conducive to their appearance.

12 Tips To Keep Unwanted Insects Out Of Compost

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Insects in my compost: what to do?

When you find soldier fly larvae and midges in your compost, it means that it is too sweet. Indeed, fruits and sugar attract them and encourage them to lay eggs. If you notice their presence, regulate your fruit intake for a while. Similarly, compost that is too dry will attract ants. If they are not a nuisance, they can quickly become invasive. Add grass clippings or soak cardboard in water and add it to the compost. This will moisten it. In the summer, place your compost bin in a cool place to prevent the waste from macerating. You should also know that your bin does not have to be watertight. It must have openings so that its temperature regulates itself.

How to maintain your compost and deal with parasites?

Compost maintenance is essential to avoid the proliferation of insects and parasites. First of all, if you have a balcony, why not install your composter on this outdoor space? Your interior will not be invaded by flies and gnats. Also, remember to cover your compost and to clean it regularly as well as its lid to avoid the invasion of harmful insects.

1. Protecting the compost from the sun
Your compost bin can be exposed to the sun during the year, but not in the summer. Indeed, during the hot season, your compost must be placed in a cool place to regulate the maceration of waste. This attracts flies and midges.

2. Controlling humidity
In a compost, too much humidity will attract flies and gnats, while too little humidity will prevent micro-organisms from surviving and thus interrupt the transformation process. It is therefore necessary to have a balanced humidity level. To achieve this, aerate and mix the waste regularly. During the first two months, mix the preparation from time to time.

3. What to do if the acidity is too high?
Similarly, in compost, the acidity of the mixture should not be too high. If you find that it is, add a handful of ashes or some crushed eggshells to the composter once a week.

4. Covering the compost
To keep gnats and unwanted insects away, add a cover to your compost. The cover can be made of pieces of cardboard, wood or dry leaves.

5. Discard waste quickly
Midges lay their eggs in rotting food. Therefore, it is essential to put food scraps in the compost before they rot. The worms will have time to transform them before the pests lay their eggs in them. If you don’t put your food scraps in the composter right away, you can store them in a bucket and put them in the refrigerator. During the summer, get into the habit of doing this routinely, since hot weather breaks down waste more quickly.

6. Aerating the composterThe composter should not be a sealed container, it should have many openings to regulate the temperature inside and limit darkness. Indeed, flies are attracted by humidity, heat and darkness.

7. Limiting sweet waste
During the summer and spring, avoid composting leftover foods that are too sweet or juicy, such as fruit. Flies and midges like to lay their eggs in these sweet wastes.

8. Clean the edges of the compost regularly
Just as you need to carefully clean the inside of your compost, don’t forget the edges. Drosophila flies like to lay their eggs in these two places

9. Cleaning the lid
If you have a plastic composter with a lid, remember to clean it regularly to keep insects at bay.

10. Suppress all the midges
Place flycatchers or a sweet liquid near the open compost to attract the midges. Repeat until they are gone. You can also cover your compost with fresh potting soil or soil to smother any remaining gnats. Stop adding new waste for a few days until the last gnats are gone.

11. An extra tip
If you eat a lot of fruit, wrap the leftovers in paper or cardboard, put them in the bottom of the composter and cover with the rest of the waste.

12. Intermingling waste
Remember to alternate dry and wet waste and not to exceed 20 cm of each organic material.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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