January 08, 2023

Gnats, Nadiring, and Neem

If you're just finding my blog, this indoor worm bin was started around Halloween. The working tray at the top of the photo was filled with moistened PittMoss Prime, a peat-free newsprint-based medium. The worms are really happy in it. Torn up cardboard? Not so much. I've read many posts saying worms love corrugated cardboard, but I never see worms on it and it's gone moldy, which isn't bad per se but I don't like it.

What I like even less are the fungus gnats and composting mites in the bin. In an outdoor bin these cohabitants would not necessarily be pests. In an indoor scenario, they are. I've lost a couple of houseplants to gnats, and I'm tired of them landing on my dinner plate.

The Wow Worm Farm in parts. It's really a neat little system.

I decided to nadir today, hoping the worms will drop down into the clean bedding but the gnats will stay in the top tray. As before, I inoculated the fresh bedding with neem seed meal but I did not moisten it at all this time. Not that they can't survive it, but gnats don't like dry. Anyway, I buried about a pint of kitchen waste in the center. Vegetable scraps produce quite a bit of moisture so I figure it'll provide what the worms need. The worms are probably pretty hungry because I haven't fed them in about 3 weeks. Reducing the amount of decaying matter seems to have helped knock down the mite population, but obviously worm activity is down, too. I'm hoping the worms' egg cases can lay dormant longer than the fungus gnat eggs can, and that I waited long enough. Maybe I should've waited a month. Ugh, I'm simply at my wit's end with these gnats!

Reassembling the Wow Worm Farm. From left to right, the base with filter to keep the worms and compost out of the leach tray, the top level where all the action is currently, the just-filled-with-bedding tray, the lid.

I am a little worried because now that I'm using both levels, I won't be able to leave the lid off. Managing moisture is key to beating the gnats and mites. Both thrive in a moist environment. If it weren't winter, I'd leave the bin outside with the lid off so the gnats could fly away and the light would drive the worms down.

Since I can't leave it open in my kitchen, I am really hoping the neem seed meal kills the gnats. If it doesn't I'll have a two-tray gnat farm. I've read it works against a plethora of pests but I haven't seen anything specifically about composting mites. I treated both trays with a generous layer of the powder and will let you know what happens.

December 17, 2022


The similarities between a colony of worms to a colony of bees continues. 

My worm bin has mites. They look very much like varroa mites, only smaller! About the size of the period at the end of this sentence. Most Internet sources say the mites are harmless, that they're a common co-habitant. My issue with them is I found a pile of them about 5 feet away from the worm bin which, I remind you, is in my kitchen. Had a bag of potting mix not been there for them to congregate under, who knows where I would've found them? I need to get them under control.

Enlarged video of a mite on a egg carton (ideal bedding BTW).
Even more enlarged photo of a mite on a paper towel, head to the left.

Where did they come from in the first place?

From Jim's Worm Farm. Despite negative reviews, and the website stating, "We strive to maintain insect/mite free orders! However,…" I was definitely wishfully thinking when I bought worms from them. So the lesson is, if you're establishing a worm bin, find a friend who has a mite-free vermicomposter who can give you a quart of worms in finished compost. A nuc as it were.

If you click on this photo of my Worm Farm's leach tray, the barely visible dark specks are composting mites.
How to control composting mites?

Even if mites are normal in a worm bin population, they can become overpopulous. Apparently, too much moisture and mites proliferate. Indeed, I find them in the leach tray, which collects excess moisture.

Besides adding additional Neem Bliss, here's everything I'm doing and why, in order of what I think will be most effective:

  1. Manage moisture so nothing is in the leach tray.*
  2. Don't feed anything in the cucurbit family, which seems to be the mites' fave. (Big oops on the double dose of butternut squash skin.) 
  3. Reduce pH. Acidity brings mites. Eggshells can provide all the calcium carbonate the soil needs, which helps to lower the soil's pH level and make it more alkaline as opposed to acidic. 
  4. Sprinkle diatomaceous earth over the bedding. DE supposedly is deadly to mites but not harmful to earthworms. However, it only works when it's dry so won't be effective unless I properly manage moisture.
Forget trapping. Sticky traps are minimally effective. Akin to using drones to collect varroa mites, supposedly mellons/squash can be used to collect the composting mites to then be tossed outside. I steamed a butternut and left a pile of guts on a yogurt lid in the upper tray overnight. Very little interest, so mellons/squash being highly attractive is Internet myth.

The bottom tray is where all the action is: worms, mites and gnats feeding on moist bedding and kitchen scraps. I'm using the top tray like a Warré hive quilt. It is filled with dry bedding that is wicking moisture from the colony below. I'm dismayed that there's quite a few mites running around up there.

What's Neem Bliss?

Besides earthworms and mites, fungus gnats just adore a moist medium of decaying plant matter. They definitely found my worm bin but a couple of doses of Neem Bliss (neem seed meal) appears to be resolving the problem. Neem Bliss successfully eradicated an outright infestation in a bag of Fort Vee compost stored in my garage. The gnats originated in another bag of potting mix on the other side of the garage. If anyone tells you that gnats are weak flyers, then you might also like to know that wolverines make great pets. Anyway, I simply thoroughly mixed in about a half-cup of the neem seed meal and set the bag outside for three weeks.** Not one gnat to be seen now! So I began using the meal on some houseplants that have been quarantined for months. I've had way more success with Neem Bliss than anything else I've tried on my houseplants, including sticky traps, DE, hydrogen peroxide, soapy water, Root Cleaner and Sacred Soil Tonic. It's been a real battle! I truly hope it takes care of the gnats – and maybe the mites? – in the worm bin, or I'm going to have to start over. Have you ever beaten a fungus gnat problem? How did you do it?

*"The notion that a worm bin should be producing leachate is one of the biggest misconceptions that I feel a need to correct. While all leachate isn’t stinky or hazardous (some may even be beneficial!), it is NOT a desirable by-product of a well-managed worm bin. It indicates too much watering, too much feeding, or not enough bedding added relative to food added." https://urbanwormcompany.com/vermicomposting-ultimate-guide-beginner-expert/

**The 3-week life cycle of fungus gnats is almost the same as varroa, and understanding it is critical to combatting the pests. See "A look under the cap.pdf".

You may also be interested in http://www.littlebigharvest.com/2014/07/controlling-mites-in-your-worm-bin.html