Fruit flies may be annoying, but it’s still important to quantify how much of a problem they are. These tiny little critters don’t have teeth, and they don’t bite. In the composting cycle, they are considered a primary consumer, which mean they break down compost material (especially fruit acid).

These little flies are vinegar flies or drosophila, and the reason why they’re found in the compost bin or worm farm is because they feed on and breed in rotting fruit and vegetable matter, and their larvae (maggots) feed on micro-organisms. They’re short-lived, with a lifespan of around 50 days.

In a ‘cold’ normal compost bin, the eggs in the food hatch into maggots (you can see house fly maggots, but not fruit fly ones) and eventually a fly or in extreme cases a swarm of fruit flies exit when the compost bin lid is taken off. As the lid is closed they are trapped.

Having a fly in your soup is one thing but having a fly near your compost heap seems quite another. Oddly enough, neither of these things is actually agreeable. No one wants a fly in or on their food, and having flies on one’s compost is just as bad for your composting efforts as it is for your overall hygiene.

If you have a problem with flies in compost bin, begin by turning and then raking the pile every day. Continue this until the larva die and the flies move on. When the problem is fixed, or the air cools down considerably, reduce the turning and raking to twice a week.

Splash your compost thoroughly with steaming water and then shut off the container’s lid tightly to hold in the heat. The heat inside the container will instantly kill the gnats living in there as well their eggs.

To get rid of vinegar flies add some dry material on top. Unless you have an enclosed compost bin, it’s best not to use meat scraps or cheese as they attract vermin. If you’re the kind of composter that only has kitchen scraps, keep some sugar cane mulch or a bale of pea straw by the compost bin.

Most commercially available composts have been sterilised, so they don’t contain fungus gnat larvae. If you cover the surface of the compost with a 1cm-thick mulch of gravel, grit or ornamental glass pebbles, this will stop flies from laying their eggs.

It’s not uncommon to see tiny brown or black flies hovering around your house plants. Take a closer look and you’ll see them scuttling over the compost too. These are fungus gnats, also known as sciarid flies. Their tiny worm-like larvae live in the top 5-8cm of compost, where they feed on algae, fungi and plant roots.

To get these bugs out of your compost, raise the heap’s temperature to above 120°F. (If you aren’t sure what your pile’s temperature is, measure it with a compost thermometer or a regular old meat thermometer wrapped in plastic.) Turn the pile over and rebuild it, watering it well as you go.