Coffee grounds have a lot of nitrogen, so they do tend to heat up when they decompose. If you are thinking of starting a larger-scale operation, I'd suggest pre-composting the coffee grounds and shredded paper first, so as to complete the heating-up cycle, and then feed the worms on the resulting compost. That does mean more labor and/or mechanization to enable you to handle and turn the compost.

I would not worry about the worms needing a "more rounded" diet, because they are not eating the coffee grounds and paper at all, but rather the diverse array of microorganisms that come to eat the coffee grounds of paper, which make for a very complete worm diet.

Here's a very good guide to larger-scale vermicomposting: http://www.organicagcentre.ca/DOCs/Vermiculture_FarmersManual_gm.pdf

Steve, That's a good word of caution. In my smaller bin the "green" coffee grounds and the "brown" paper bedding probably has not been in sufficient quantities to heat up. But if I scale to the level it looks like I might be able to, this may become a concern. Thanks.

I do have 4 bins right now. I think what I'm going to do at first is just create a 5th larger bin. I'll put the bucket of coffee grounds on one side and the contents of one of my other worm bins on the other. If the worms like the coffee they will migrate over at their own pace. At least that's the theory.

Parsley, Thanks for that. The well rounded diet part is extremely helpful. And thanks for the link to the Manual. Reading it now. Very cool.

Don... you're right that small scale worm bin composting tends to not have quite the critical mass necessary to achieve the 160-180F temp range of larger composting piles but don't completely disregard temp differentials within the worm bin. Last winter I would frequently poked around my bins (down in the basement where ambient temps ranged ~65F) with an IR pyrometer and found 20F differentials within a foot of each other not uncommon. I even found a couple locations registering near 97F at times... that's enough to cause the worms to stay away... they seem to begin returning when the temps dropped to below 85F. Those temperature hot-spots came from deposits of green juice pulp and powdered grains mostly. However you've got the right idea to feed only over on one end of the bin so the worms will have the other end to wait out the heat-wave in.

The worms may not need a rounded diet but do keep in mind where you intend the castings to go... if its going into the garden or into container pots then the plants could maybe use a well rounded diet. Crushed eggshells will add calcium and kitchen refuse (plant matter) will add many minerals... which will wind up in chelated forms, excellent for feeding plants. Also carbohydrates are needed by many soil organisms for energy and amino acids to build... healthy soil organisms support healthy plant life. All manner of vegetable/fruit and grain (like stale bread, etc) wind up in our worm bin instead of the trash. We are up to six 30-gallon bins from which I harvested 90 gallons of quality vermicompost this fall and expect to continue to do every 6 months. I supplement their diet with layer mash from the feed store when our kitchen scraps are not enough... can't beat 40-lbs for under $12... the stuff is so nutrient dense just half of that will last all winter. Ultimately the cycle will be complete when the castings go into the soil and the plants incorporate it.

Coffee grounds are good... fortunately not having eyes, worms never go to sleep so they'll be able to handle the caffeine (its a joke).

Monomer, thank you. The temperature thing is interesting. I've never noticed mine heating up, but then again I've never really paid attention to it. I'm going to start checking mine. Its in the 60's hear right now and I keep my bins outside. If it weren't pouring down rain, I'd go out now and stick my hand in there just to check. lol

The chicken feed for worms is fascinating too. I have chickens, so I might sprinkle a little layer pellets in there just for fun. My worm pen isn't rodent proof, so I probably shouldn't make a habit of that. In fact the rubbermaid tote that is now my worm bin used to be my chicken feed container, until mice ate a whole in it. I now keep the feed in a metal container.

BTW, I have wondered about the caffeine content effects on the worms. I have not noticed my red wigglers doing Alabama jumper impersonations or anything.

I powder-up the layer mash first with a Vitamix blender... its what I've got but you could use a coffee grinder or any kitchen blender. Powdered, it will disappear much quicker... a thin layer will be gone in a couple days... a thicker layer lasts longer (I usually put down a half inch or thicker of powdered mash, which requires some watering or else it will turn into a hard pancake... oh the worms will still nibble it away but it be a slower process). Even if you don't powder it up first, it will still disappear but it'll take significantly longer since the microbes will have to break it down into bite size pieces for the worms... that will take a LOT longer. Besides mash is made up of grain and some grit so powdering it up will blend it all together into a homogeneous mixture, which the worms can better consume and the bacteria in the worms' intestines can digest.

I put coffee grounds in my bin regularly. Sometimes I have noticed a lot of color variations among individual worms in my bin, including some that are very dark colored...almost coffee colored. It makes me wonder....

I've read a lot of articles about obtaining coffee grounds from coffee shops. If you want to get grounds for your worms, don't overlook gas stations and truck stops. In 2 weeks I've already collected 15 gallons (three 5-gal buckets full) of grounds from only two small gas stations.

The worms from my existing bin have already started to migrate over to the first 5 gal load I added a week ago.

In my small town there is only 1 starbucks and during warm months theres a lot of competition for the grounds. But during the winter months is best time to stock up as most people dont try to get them at that time.

with all that caffeine, you're keeping the worms up all night toiling away! <just kidding>

At times when I can't source from local supply over a period of time I collect my coffea pods from my machine. Once in a blue moon I tear off the top, spoon out the contents and I've an ice cream container before long. Sounds labour intensive but I have it down to a fine art

cheers