Fruit flies are such a pain to get rid of, once they’re in your house. But what do you do if your vermi composting bin has fruit flies? Sure we could always keep the bin outside, but when the temperatures are in the upper 90′s outside the poor worms will cook in our worm bin. We thought about putting the worm bin in the shop or barn, but those two places also get pretty warm when the temperatures soar. Our last resort was putting them in the house. But before they moved into the house, we needed to get rid of those pesky fruit flies!
Three Key Elements to Get Rid of Fruit Flies in a Compost Bin
I eventually discovered three key elements to keep fruit flies out of the worm composting bin while still feeding them fruit and vegetable scraps. I’ve been doing these two things for a couple weeks now and we no longer have issues with fruit flies! What does that mean? Our worms now live in the house, in a nice shady corner of the laundry room.
#1: Freeze all worm “food” before adding it to the bin.
Fruit flies lay their eggs on the skin of produce. When frozen, the eggs are killed. We now keep a gallon size plastic bag in the freezer and add produce scraps to it as we have them. Once the bag is full, I keep it in the freezer for another 24 hours just to make sure the last batch of scraps added to it have a chance to fully freeze.
After freezing the produce scraps for at least 24 hours, remove them from the freezer. Let them thaw and return to room temperature. Then they are ready to be fed to your worms. After the produce is frozen and then thawed, it all starts to turn in to a slimy mess which the worms love even more!
#2: Bury the food in the worm bin.
Instead of laying the produce scraps on top of the other materials in the bin, bury them. I keep a small hand rake by the worm bin so when I feed them I can use it to carefully rake the other materials back and bury the new food. The idea behind burying the food is that it keeps it out of reach to any flying insects, like fruit flies, that may happen to sneak into your bin. If they can’t reach it, they won’t lay eggs in it.
#3: Put damp newspaper scraps on the top layer of the compost bin.
We tore newspaper into thin 1/2″-1″ wide strips and laid it on top of the other layers of material in our worm bin. If you tear with the grain of the paper, you will be amazed at how easily it tears in nice uniform strips! Place enough newspaper strips on top so you can’t see the next layer underneath. Again the idea with this is to keep the soil layer or any food scraps poking up through inaccessible to the fruit flies to lay eggs.
Spritz water on the newspaper strips until they are damp. This is another great way to gauge the moisture level in the worm bin. For a newbie vermicomposter, trying to figure out if the bin is wet enough or too wet can be tricky. The newspaper is an easy gauge. When you check the worm bin and the newspaper is dried out, sprtiz it with water until it is damp again. If the newspaper is soaking wet, it is probably a little too wet in the bin and the lid needs to stay off for a bit. We’ve also noticed that the worms loved to eat the newspaper layer so eventually you will need to add more as they consume it.