Worm Composting

Worm composting or vermicomposting is the practice of using worms to decompose or break down organic materials such as yard debris and food scraps. The end product is called worm castings, which is full of beneficial microbes and nutrients. Worm castings are similar to compost and make a great soil amendment to grow bigger and healthier plants. For people with no backyard, limited space, or minimal amount of organics, worm composting is an alternative solution as bins can be kept indoors or anywhere that is dark and quiet.

The videos below are recorded workshops (in the English and Spanish language) with instructions on how to set up a worm bin at home. If you generate a large amount of organic material or want to create compost more quickly, please visit our home composting webpage for information on creating a backyard hot pile.

The map and list below the videos offer some resources and locations where you can purchase red wiggler worms (Eisenia fetida) for your own bin at home, or finished worm castings for your garden. You can also find assistance in setting up vermicomposting for your organization.

Virtual Vermicomposting Workshops in English and Spanish

These virtual workshops were conducted by Sonoma County Master Gardeners and translated by Soluna Outreach Solutions.

Recorded workshops are also available for creating Backyard Hot Piles, which are great for people with more space. It is better suited for composting larger amounts of material and produces compost more quickly.


The following resources are provided in English and Spanish language. Click on the image to download the .pdf

Help for the home gardener

Ask an expert! The Sonoma County Master Gardeners are available at (707) 565-2608 or mgsonoma@ucdavis.edu. Master Gardener volunteers are trained and certified by the University of California, Cooperative Extension. Workshops and seminars are given regularly at various libraries.

UC master gardener program of Sonoma County


Please indicate the city, town, or region in Sonoma County where you would like a compost giveaway event to be held. Leave your contact information if you want to be notified when an event is scheduled nearby.

The most challenging part of organizing a compost giveaway event is finding a suitable location. If you have a suggestion, feel free to type it in the message box below. The site must be large enough for a 20-40 yd truck to enter and turn around, and it must allow for people to get out of their cars and shovel compost safely. Ideally, the site should also have at least two exits for traffic flow.

Want to help? Check the box and leave a message below about how much you'd like to be involved. An event is more likely to happen if we have one or two volunteers. You can either help with the planning, or take a smaller role by simply being on site on event day to direct the cars.

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Location pin Delta Worms

4882 Cabrillo Point
Discovery Bay, CA 94505

NotesSupplier of red wiggler worms, castings, and worm extract available for purchase. Ships to Northern California. Consultation, education, and training services also available.

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Location pin Mass Wiggle

6155 Lakeville Highway
Petaluma, CA 94952

NotesBulk worm castings available for sale. Visit the website to order, or call or email Dave for a tour of his facilities.

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Location pin Sonoma County Master Gardeners

133 Aviation Blvd, STE 109
Santa Rosa, CA 95403

NotesMaster Gardener volunteers are trained and certified by the University of California Cooperative Extension. Call or email your home composting questions.

Location pin Sonoma Valley Worm Farm

1777 Watmaugh Rd
Sonoma, CA 95476

NotesRed wriggler worms, worm castings, and vermi-extract for sale. See website for more information or call to place an order. Worms shipped to Northern California locations only.

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Location pin The Compost Club

NotesOrganization assists schools and businesses in setting up vermicomposting systems. Visit the website for more info and educational resources..