I don't know how much is too much, but keep in mind that egg shells are mineral. They do not break down in the worm bin.

OK to wash? Yes. Wash them, or don't. It doesn't matter. I don't wash mine, and I don't notice any smell, except when I grind them, but I have never added more than two at a time to my bins.

If this is to feed your worms, don't bother since they don't eat them. (They will eat the membrane.) If this is to produce compost for gardening, the minerals are a good addition.

If the egg shells are ground small enough, the worms will eta them, and the calcium is good for them. If they are not ground small enough, the worms won't eat them.

I crushed some with my hands and threw them in my new bin. (I also microwaved them first)

I guess I should have ground them up tiny. Lesson learned.

Karen

I tend to put in a few in large bits. My worms love to curl up and mate in them. Especially the ones that are fairly intact cup shapes. And they do seem to break down eventually, even if that is later in the soil, so I don't worry about it. I figure giving them a motel room to make cocoons in is pretty good too.

antoniab thanks for the info! I am making breakfast for dinner tonight and may just save some 1/2 egg shells for future worm mating rooms. lol

so funny they like to have some privacy :)

Karen

Depends on what you are using the final compost for. Outside bin gets uncrushed. I don't know where they go but I never see them again.

Inside I would just crush in one hand but because I use vermicompost for seed starting I have been putting dried, non rinsed shells between two pieces of paper and rolling them with a wine bottle.

If using a machine do not breath the dust.

Ok, they are a mineral. Ok. Worms don't eat them. Do they ever melt away? Otherwise wouldn't the world be covered in egg shells? I figure a magical process happens where the calcium becomes available in the soil.