Skip to Main Content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.

Glendale Garden: Harvesting Worm Castings

Glendale School Garden

Harvesting Worm Castings: Step 1

Lift off the top bin from bottom bin. Empty "worm juice" into your garden or save in container for later additions to the garden. 

Picture: notice center bin with "worm juice". This liquid is gold! Do not discard! Use it in to your garden.

Harvesting Worm Castings: Step 2

Clean out the "juice bin". If there are any worms, add back to your top worm bin.

Clean worm bin ready for use.

Harvesting Worm Castings: Step 3

Add clean coir brick (see bin set up for coir brick details),

Add 5 liters (1.3 gallons) of very warm water over the coir brick. Stir the coir around every 5 minutes until all of the coir has soaked up all the liquid. If there is some coir that is still dry, add a little more warm water until all the coir has taken up the water. Fluff the coir brick and allow it to cool to room temperature. 

Soaking coir brick:


Harvesting Worm Castings: Step 4

Using a trowel, carefully harvest the worm castings on the half side that has not been fed for the last few weeks. Some worms will still be there. It's OK to have them go into your garden (but they probably won't survive our winter) OR you can carefully separate them out of the harvested castings and place them back on the side with all the other worms. When finished, your box will be empty on one side.

Harvested worm bin.

Optional: You will notice that the worm castings are dark, moist and clumpy. You may want to add the newly harvested worm castings to bagged garden soil, other dry compost or peat moss so that it easier to spread in your garden.


Harvesting Worm Castings: Step 5

Now, take the soaked, cooled coir and place about half in the empty side of worm bin. Add fresh food and cover with the rest of the coir.

Coir and food in harvested part of worm bin.

You can also add chopped or crushed egg shells at this time. The extra calcium helps the worms digest their food.

Added egg shells.

Notice the difference between the side that has the new coir and the side that still has the worm castings. After a few days mix both sides together and continue feeding as before.

Harvesting Worm Castings: Step 6

Mark on the bin the date and side of the most recent harvest. Use the other side at the next harvest approximately 6 months later.

Adding Worm Castings to your Garden

1. Harvested worm castings are moist and dense. Adding something to the castings makes it easier to spread in the garden. Pictured here are 2 reconstituted coir bricks ready to mix with the worm castings.

worm castings

2. Place worm casting mixture in garden bed. 

3. Mix in the worm castings into your garden soil.

Mixing in compost into the garden

Finally, don't forget about the "worm juice" in the bottom bin. It's best to check every month how much juice is in the bottom bin. This is especially important if you notice an odor coming from the bin. Simply discard the "worm juice" in your garden or potted plants. Your garden plants and planters will say "thank you"!