Fungus gnats

I get questions like this occasionally:

"When I took the lid off the bin I noticed tiny little black flies flying out... I don't think they are fruit flies because I put out a dish with mixture of cider vinegar, water and a little mild dish soap which always takes care of fruit flies but these guys could care less about it! Please help."

Most commonly these are be fungus gnats (see image). Fungus Gnats are very small 1/32 to 7/16 inch long, long legged and mosquito-like and are usually black, gray, or brown. The larvae feed on moist decaying organic matter and fungi growing in the soil.

I have found the best treatment of fungus gnats to be BTi (Bacillus thuringiensis israelenis) mosquito rings/dunks. To treat an infestation, make a solution of 2 cups of water for about 1/4 of the dunk. Remove the newspaper layer and spray about 1/2 of this solution on the soil daily for 10 days (make fresh solution every 2 days-- one piece of ring lasts 2 or 3 times). Vacuum any adults your can when you open
the lid (dust buster or shop vac work well). Keep the newspaper layer off your bin during the treatment period and do not add food. That should take care of them.

To prevent fungus gnats, be sure to bury any food scraps. If you see mold starting to grow in your bin, replace the newspaper layer and and hold food back until the worms catch up.

Cheers,

Mark

Starting your worm bin

Your worms have arrived. Hooray! Now what? I get this question a lot, so here are the step-by-step instructions to get your bin started. I am doing this outside to be sure we have enough light for the photos. I typically start new bins indoors.

Step 1. Gather your materials. You will need your bin, your worms, some food, and newspaper. You should have about half as much food as you have worms. I’m starting with a pound of worms and a half pound of food (such as old salad greens, coffee grounds, tea bags, egg shells, and banana peels).

Step 2. Put your food in first. Food always goes in the bottom of your worm bin. Your worms will be able to find the food more easily, it will break down faster, and it won’t attract fruit flies. Start feeding in one corner and your worms will completely cover the food.
Step 3. Add your worms. Put them directly on top of the food. Your worms will eat this food as it breaks down and you want them tin contact with it. The next time I feed them, I will put the food in the adjacent corner (the empty corner on the right side of the photo).


Step 4 Add newspaper. Now you fill your bin with shredded newspaper (or other bedding). That is all you need to start your bin. No soil is necessary!

Step 5. Fill your bin to within about 3-4 inches of the top (push down gently to be sure the newspaper is in contact with the worms). You’re finished! Mark your bin with a sticky note where the worms are.

Feed in the adjacent (in the case of my photo) counter-clockwise corner next. In the case of this bin, I will again add ½ pound of food next week ( the same in the 3^rd and 4^th corners the following weeks). When I get back to my original corner, I will feed ¾ pound of food in the corners for the following 4 weeks. When I complete this cycle, I will add 1 pound of food per week. At this point your worms should be close to double the number you originally received and able to keep up.

Remember, don’t overfeed and always put the food on the bottom under the worms. Then cover with newspaper. If you smell rotting food or see mold or fungus in your bin) add less food until the worms catch up.

Cheers,

Mark

What is the best size for my worm bin?

Really that is determined by what works for you in the space you have.

You can buy manufactured bins online or in progressive stores, but I suggest you save your money and make one yourself!

When I respond to this question, I offer the following suggestions and considerations:

Red wigglers don’t typically dig more than 8” deep into a worm bin, so a really deep bin does not work as well as a shallower bin. You want to have the worms all the way to the bottom of the bin to keep conditions aerobic.

Really large bins (30 or 50 gallon size) can be used for worm bins, but they are VERY heavy when full of worms and vermicompost. If you’re planning to move your bin (e.g., take it outside to harvest using the sun), consider a series of smaller bins. If you're not going to move it, these large bins can certainly work.

Small bins can also work. Some people have shoebox size bins they keep under the kitchen sink. This can work, however, you must closely monitor conditions in your bin and be careful what you feed them. In a small bin the worms have nowhere to escape if the conditions become unhealthy. A friend had a wonderful bin until a bunch of limes were added in a layer to the bin after a Cinco de Mayo party. Soil pH dropped and all the worms died. This is also why I recommend you feed in the corners when you are starting.

I find the standard 18 gallon plastic storage totes work well for me. They are reasonably sized to allow the worms to flee from any bad things you may add, they are not too when full, they don’t take up too much space in the room, and they can be stacked. See http://www.wormmainea.com/Worm_Bin_Instructions.pdf for free instructions for building a WormMainea style worm bin).

The size and style of your worm bin is not important. If it works for you then it is best. The most important thing is that you get started with a worm bin.

Cheers,

Mark