SGV Tribune

Master Gardener: How to compost with worms

Vermicomposting can be done inside any time of the year, which makes it a perfect rainy-day activity for children.

One of the many gardening-related activities we’ve enjoyed for several years is vermicomposting. Vermicomposting is simply composting with worms. It can be done inside any time of the year, which makes it a perfect rainy-day activity for children.

You may have read about the many benefits of fertilizing your plants with worm castings. They contain microorganisms that contribute to soil health. They contain nutrients such as nitrogen, phosphorus, potassium, iron, calcium and sulfur. The composition of worm castings allows for a slower release of nutrients which is more beneficial than chemical fertilizers which tend to produce run-off.

Compost and vermicompost tea are safe foliar treatments for plants. You can brew a batch by filling a 5-gallon bucket with water, adding a cup or two of compost, and letting it sit for 24 hours. Stir once or twice to aerate. Alternatively, you can aerate using an aquarium pump, tubing and air stone. Filter the finished solution and spray on any plants that could use a little boost.

If you are interested in raising your own worms, you can purchase a ready-made bin from the internet or build one yourself. We were lucky enough to find one through our local master composter program, but that may not be an option in many places.

To make your own worm bin, you will need 3 plastic storage bins or 5-gallon buckets. It is important that they can be stacked. Take 2 of these containers and drill 1/4-inch holes all over the bottom. You want enough holes so that the worms can easily travel from one container to the next, but not so many that you totally obliterate the structural integrity of the container. Leave the third container intact.

Next, drill 1/8-inch holes along the sides of the container, under the lip. These are for air circulation. Likewise, drill 1/8-inch holes all over one of the lids. This will allow for more air circulation.

To assemble, place one of the drilled containers inside the container that has not been drilled. Next, you will add nesting material.

We like to use shredded paper that has been dunked in water and squeezed out. When placing the paper into the bin, make sure to fluff it up so that there’s no matted material.

Rehydrated coir bricks work as well. Again, make sure the material is moist but fluffed up so that the worms will have room to move around.

Place the bin in an area that is protected from extreme heat or cold. Avoid areas prone to vibration, such as a laundry room.

Now, you can add the worms. Red wigglers are available at most bait shops or through mail order farm supply sources. Don’t forget to put the lid on!

Feed your worms once or twice a week with kitchen waste that you would normally compost. Once they are established and have consumed most of their bedding, place fresh bedding into the third bin and place it on top of the second bin. When you start adding food to the third bin, the worms will migrate up and you will have finished compost in the middle bin.

Have gardening questions? Email

Looking for more gardening tips? Here’s how to contact the Master Gardener program in your area.

Los Angeles County; 626-586-1988;

Orange County; 949-809-9760;

Riverside County; 951-683-6491 ext. 231;

San Bernardino County; 909-387-2182;