Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Advice from the UC MGCC Help Desk: Thank you for contacting the Master Gardener help desk with your question about compost and rodents.
There are several different designs for compost bins to prevent rodent access, all of which have their benefits and disadvantages. The easiest way to keep rodents out would be a fully-enclosed and elevated tumbling bin, however these bins tend to be smaller than other bins. There are also plastic on-the-ground bins that hold more, but are more difficult to rodent proof, although it's definitely possible. Then there are wooden bins or open compost piles that pretty much cannot be rodent proofed.
There are some steps you can also take to reduce the attractiveness of compost in any container. Since rodents use the bins to find food and often as well a dry and comfortable place to live, make sure you keep the pile moist and turn it regularly. Bury and cover food waste deeply into the compost, making sure you don't add meat, grease or dairy products.
There are other things you can do to reduce rodent population in your yard. Don't feed and/or leave uneaten pet food outside. Cleanup around bird-feeding stations where the birds have scatter food. Clear thick vegetation, especially ground covers. Keep garbage and trash picked up and stored in a container. Seal access to crawl spaces and attics as well as make the area under decks and sheds inaccessible. The goal is to to eliminate rodents' cover and hiding spots.
This year especially, rat complaints at the MGCC Help Desks appear to be quite common. Rats appear to be a bigger problem in our area than are mice, and roof rats are the primary pest. Rats can chew and cause damage inside homes, especially attics and crawl spaces, and they can get into stored foods, especially pet food in garages. In the garden, they can damage fruits and vegetables, sometimes wiping out entire crops. They can also spread diseases to humans and other animals.
The University of California has a good information sheet on rat management for the home and garden: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74106.html. And here are two links to good information about composting: http://anrcatalog.ucanr.edu/pdf/8037.pdf and http://sacmg.ucanr.edu/files/163139.pdf.
Additionally, if you live in Contra Costa County, you can request assistance on rat and mice control from the Contra Costa Mosquito & Vector Control District. While the District won't trap or bait for rats and mice in or around private e homes, they will assist homeowners with rat or mouse problems with advice and a free inspection from one of their state certified technicians to assist in rodent prevention and control (skunks too!). Their web page at http://www.contracostamosquito.com/rats_mice.htm provides the details.
Please let us know if you have more questions.
(all pictures from the Contra Costa Mosquito & Vector Control District)
Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: firstname.lastname@example.org, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/).