Worm Bin Health

Question

This is my first post on the Sustainable Living stack exchange, which I did not know existed. I am extremely excited to become an active member on this exchange, because I try to live as sustainable as I possibly can, and love discussion.

Recently, I have invested in a worm bin for my college dorm room. It has been going great for about two months; the worms even underwent a reproduction phase where there were many small baby worms in the bin. I typically did not over react / over protect the worms, and just let them work. After feeding them multiple apples in a row, however, I started to notice that the worms (especially the small ones) balled up into a mass. It was very difficult to determine why, as the "squeeze test" and my moisture meter said that it was properly moist (although perhaps I was reading them incorrectly). I read on some sources that overfeeding nutrient rich food can lead to some form of poisoning. To address this, and the potential high moisture levels, I added a significant (1/4 block) amount of coir and some paper bedding. Then I noticed it was too dry and added some water (about two days later).

Ever since then my worms have appeared to be very weak and not healthy. The worm bin has always smelled very good and earthy, but the worms themselves don't seem to reflect that. I check the moisture levels every so often; I believe I am on the upper end of the "ok" range for moisture. I notice very little activity at the top of the bin. Just recently (just before typing this), I mixed the bin and noticed that there were a significant amount of variously sized worms near the bottom. Yet, to me, the bottom felt extremely moist (like a damp sponge). Additionally, the worms are not eating the small apple bits I just gave them (2 days ago, I have about a pound of worms). Finally, more worms than before have fallen (or have crawled) into the collection basin of the worm bin, yet none of them are trying to escape the top sides of the bin.

My questions: What could be going wrong with my bin? Is it the moisture? Is it over-feeding? Is it a mix of both? My moisture meter, that came with the bin, gives me a reading of about 5-6.5 everywhere in the bin (about 1"-2" deep).

Is my worm bin fine now, and I should just calm down and let them readjust? Would it be better to restart somehow, or should I just let time take its course?

Finally, is there any definite way to determining the health of the worms? I.e. could I sacrifice a sample of the worms to analyze? Am I overthinking this?

I've read How can I tell whether my earthworms are healthy?, although I don't feel it perfectly answers my situation.

Answer 1

The variously sized worms lower in your bin are a good sign. Apparently they are still procreating, so there doesn't seem to be an immediate danger of extinction. You mentioned that the bottom of your bin feels like a damp sponge. That is more or less the moisture level you should be aiming for; a damp, wrung-out sponge. Some types of worms, like the European Nightcrawler, prefer their living conditions a bit wetter than the more commonly-used Red Wiggler. In case of doubt, it's better to make your bin wetter rather than drier.

I'm not 100% sure a lack of water explains the balled up worms. When the top is too dry, I'd expect all worms to crawl down a bit deeper and be okay. The only explanation I can think of is that hungry worms go to the top for food and then dry out. Besides adding more water, you can try and bury some food deeper down and see how the worms like that.

If the moisture level isn't the problem I can think of several other potential causes (but they seem less likely):

• Overfeeding: many new vermicomposters tend to overfeed a bin in the beginning. Only add new food when the old food in the bin has shrunk quite a bit or has almost disappeared. Later on when your bin is more mature you can increase the feeding rate. However overfeeding will usually make a bin start to smell and from your description it doesn't look like this is the case.

• Harmful foods: some people claim that their worms were affected by pesticides on fruit peels. Especially bananas, apples and citrus fruits have a reputation for having lots of pesticides. It's difficult to verify these claims, but in theory it's certainly possible that a particular batch of food contains an unusually large amount of pesticides and that the worms were affected. If you want to be on the safe side, try feeding your worms organic food as much as possible. When starting a bin, I also recommend not feeding citrus foods and unions. Later on you can add these in small quantities. Never feed worms meat, dairy or salty, spicy or oily foods.

• Too much nitrogen: I'm sure you know you need to keep a good balance between greens (nitrogen-rich food) and browns when feeding your worms. It's not necessary to use a C:N ratio calculator as some fanatic composters do to keep an ideal ratio of 25:1, just mixing greens and browns regularly works fine. However keep in mind that the C:N ratio is different from the volumes you feed the worms. Roughly you need to keep a 30:70 volume ratio of green and brown material.

AFAIK there are no possibilities to determine the cause of your problem other than experimenting a bit and see if your worms improve. When experimenting do this only in a part of the bin if possible, so worms have a chance to escape to safer, unaffected parts if your experiment fails. This is also a good tactic for adding new food. If decomposing foods heat up too much, worms should have room to escape.