How do I keep worm compost from turning into a hot compost?

I have a compost tumbler that I've been throwing random kitchen/yard scraps into. I add water occasionally and turn every few days, but it never seems to "heat up" like they say it's supposed to. In the past I've gotten it to heat a little by adding blood meal, but I would rather not do that because it's expensive. I was wondering if I could just add worms to the bin and stop the manual tumbling. How can I be sure that the compost won't turn into a hot compost pile and heat up? From what I've read you add basically the same ingredients to a worm bin that you add to a hot compost pile. So what's the difference?
Thanks in advance!

Compost gets hot when there is plenty of nitrogen to feed the microorganisms, yet enough coarse material to keep some channels open so it is well oxygenated. Tumbling and adding blood meal are doing this for you. You can try other sources of nitrogen, such as grass clippings, and other soft green plant material, such as trimmings from annual or perennial (non woody) plants to add to the woody garden trimmings.
Also, the insulation of a large pile keeps the heat in, so that you can feel the heat at the top (heat rises) but to feel the heat from the side you need to dig into the pile.

The opposite of this keeps worm beds cool:
They still need oxygen, so do not skimp on the coarse matter.
Minimize high protein materials. Do not over load the system with too much green matter and no animal based matter (protein means, among other things, nitrogen)
Most of the worm bedding is not nitrogen, but carbon. Paper, peat moss, coir and so on.

Small volume, or if it is a large volume, it is spread out, a thin layer. Since heat rises, any heat generated in a large, but shallow box will leave. A small volume also will stay cooler because the heat can leave on all sides. If you are interested in the math, there, look up the 'Square-Cube' ratio.


This message was edited Dec 15, 2012 11:48 AM

passifloria, vermicomposting is actually considered 'cold' composting. The optimum temperature is 68F which is also the optimum temperature for vermiculturing. I have four bins sitting on a thick carpet in an unheated attached garage which can get down in the 40's during the winter months which is also the temperature of the bin media, and the worms will do fine. However, I use a toggle timer with a heat pad to adjust the temperature back into the optimum range. If you get your bins too hot, say 90F or above, the worms will run to the coolest place they can find, either in the corners of the bin(s) or outside of the bin(s).

I add green grass clippings (organic)and other green material to help keep the heat going. Compost needs green materials, carbon materials, (straw, leaves, etc) and then the kitchen waste, egg shells (crushed), and among anumber of friends who have compost tumblers, most have given up on them and gone to a pile, layered with the materials noted above. I also add worms, because if the pile gets too hot, they move out. But will help break stuff down.

Adding blood meal, alfalfa meal, fish meal, seaweed meal in small amounts may improve what you are trying to do in teh composter

I have added blood meal left over from the season before to one of my outdoor compost bins nancy and I would agree with you on the other ingredients except for large scale production like the windrow method. My available materials include horse and cow manure, rotted hay or straw, wood chip fines, coffee grounds, and possibly leaves in the fall. The often raised question concerning heat especially for the folks in the south is to turn the pile(s) often and water when doing so. A simple meat thermometer can tell you when things are getting a bit too hot. Red wigglers are actually far more tolerent of heat than regular earthworms and their activity levels are much better than regular earth worms in compost piles.Tossing a tarp over the top of the compost pile helps me to maintain moisture levels. With our cool temperatures and drops as much as 40 degrees at night we have little difficulty with heat in our outdoor compost piles.

I'm not sure what type of grass you have there in OR nancy, but I avoid using grass cuttings because of the seed problem. My compost may not be sufficiently hot to destroy grass seed and it is a real pain once it gets started in the garden.