Using Worm Castings in the Garden

As many gardeners become aware of the benefits of growing organically, the demand for natural fertilizers is rising. Worm castings are an excellent option for amending tired soil and creating new garden beds. Although some find the concept of using worm poop in their garden unpalatable, the benefits far outweigh any “ewww” factors.

Amending Soil with Organic Matter

Adding organic matter to the soil is an integral step to keeping it healthy and while compost, manure, chopped leaves and grass are all excellent sources, worm castings go one step further. In addition to helping plants become more drought tolerant by improving soil tilth, aeration and water absorption, worm castings will also provide a source of slow release nutrients available to the plant as it is needed. Although the NPK value of castings is low compared to chemical fertilizers, the slow release and the lack of synthetic products in the soil promotes microbes and bacteria to grow at a healthy rate keeping fungal infections down and promoting healthy root growth.

How to Make or Purchase Worm Castings

Many worm castings users choose to become worm farmers. Vermicomposting is fairly easy, cheap and does not take much time. Systems range from a simple plastic container to specialized systems but all are based on the idea of feeding worms (usually red wigglers, Eisenia foetida) kitchen scraps and harvesting the worm castings for garden use. But you don’t have to have worms in your kitchen to have access to this great resource. Redworms can also be used right in the compost heap to help speed up decomposition and deposit castings within the heap. In cooler areas, the compost pile will need to be “hot” since redworms can only live in a range of 55 to 75 degrees. Many garden catalogs also sell peletized worm eggs that can be scattered in the garden to hatch. Although this will not allow the gardener to have control over the exact areas or plants that are fertilized, it is still a great way to add nutrients to the soil. Of course, castings can also be purchased at garden supply and hydroponic growing stores as well as online.

Worm Casting Compost Tea

In addition to straight worm castings, castings tea is a wonderful way to fertilize house plants and container plants when you don’t want to add additional bulk to the containers. You can buy worm castings tea from a company like Terracycle but it is also easy to make by putting a few cups of castings in some non-cholorinated water and allowing it to steep for about a day.

How to Use Worm Castings in the Garden

When building a new garden bed, worm castings can be used fairly liberally as long as it is mixed in well. A good potting mix for containers consists of fifty percent worm castings and fifty percent soil. To add castings to existing beds, top dress or side dress plants with one half to one full cup of castings every month of the growing season. Worm castings are safe to handle and contain no odor but care should be taken to wash hands after working with them.