Adding Earthworms to Raised Beds


We’ve had 3 large (10′ x 3′ x 27″ high) planter boxes built and filled them with CIL Enriched Triple Mix and a thick layer of cedar mulch. I want to introduce some earthworms into the soil but given the height of the boxes there’s no way the worms are going to make it in on their own. Your answer to a previous question concerning worms suggested red wigglers or nightcrawlers; do you think they would survive in triple mix with added mulch? If so, do you have any suggestions as to where I might find a “worm-monger” to purchase some? Many thanks for your help!


Thanks for contacting Toronto Master Gardeners. Red wigglers eat organic material in a garden helping to break it down and release plant available nutrients, beneficial microbes and plant growth hormone.
To survive red wigglers need something to eat. They will not survive on earth alone. Red worms fall into the “epigeic,” or “upon the earth,” worm category. These worms live along the surface of the soil in decaying matter. Next spring when the temperature is 12 degrees Celsius or above would be the best time to add red wigglers to the boxes. You can incorporate them by creating  vermicomposting trenches in the boxes. This is like a compost bin in the ground. First create trenches that are 6 – 8 inches deep. You can choose the width or length. Add some shredded corrugated cardboard or newspaper, partially decomposed plant matter from the yard, vegetable scraps, red worms and a layer of cardboard or yard matter on top of that. The worms will recycle the decaying matter into nutrients for your garden plants. To keep them alive, you have to continue to feed the worms decaying matter until the weather becomes cold.

When the weather becomes cold, the goal is not to create compost but rather keep the worms alive during winter. At this point you need to stop feeding them. Insulate the compost heaps with 2 to 3 feet of leaves or hay, and then cover the piles with a waterproof tarp. This will keep the air sufficiently warm and keep out snow, ice, and rain. When the air warms up to 12 degrees Celsius uncover the piles and start feeding the worms again.

If this seems too complicated but you still want to benefit from the red worm compost, you might consider starting a separate vermicomposting bin and adding the compost to your planter boxes. Toronto Master Gardeners does not make specific recommendations for businesses but if you look on line you will see that are places where you can buy red wigglers. For more information on red wigglers and vermicomposting please see the following links: