Hooked on Worm Castings

My husband’s got worms and I couldn’t be more thrilled. Because his worms eat food scraps and produce a nectar-like waste product – worm castings.

worms in feeding tray
Our worms have produced rich compost — and more worms!

With vermicomposting, he’s producing a soil amendment (humus) full of more than 60 micronutrients and trace minerals to gently and naturally support plant growth. Worm castings are the excrement left by worms, and the worm tower he uses for vermicomposting makes it easy to feed the worms and harvest their castings.

worm-castings-in-bin
Worm castings in the collection tray ready to sift through and harvest.

Benefits of Worm Castings

  • Castings hold all sorts of live micronutrients that help plants better absorb nutrients from soil, especially soil with low or high pH.
  • The worm castings can help repel some pests such as white flies and aphids; an enzyme in the castings is offensive to pests.
  • Feeding worms food scraps reduces and recycles garbage throughout the year.
  • Worm castings do not stink!
succulent-added-castings
This potted succulent didn’t bloom until it got about a tablespoon of worm castings.

How a Worm Bin Works

worm-factory-bin
A Nature’s Footprint Worm Factory has trays with levels to feed worms and make compost.

Tim purchased a Worm Factory from Nature’s Footprint a few years ago. He keeps it in a corner of the garage for easy access and protection. Vermicomposting works with upward migration. The worms move up to eat, and gravity sends moisture and castings to the bottom. Adding food at the top every so often (when worms are actively eating the last food you added and are moving to the top tray) keeps the worms continuously fed and reproducing. The worms eat paper, fruit and vegetable scraps, bread, coffee grounds and eggshells, along with other scraps. The bedding added to each level eventually breaks down into castings as well.

worm-bin-food-tray
The food tray with bedding sits on top and worms move up to eat.

The resulting compost is thick, dark and crumbly. Its ready to use as soon as you harvest. Some of the best uses are to mix the castings in with garden soil as an amendment or to top dress container plants. We added castings to some of our vegetable starts last year a few weeks after planting, just loosely scratching the castings into the soil around the plants. It takes less worm compost to improve soil than regular compost.  Finally, use worm castings to make compost tea.

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We now have nearly 3 gallons of worm compost in this bucket. A fitted lid keeps it airtight.

A Few Tips

Keep the tower warm in winter. You might have to either move a worm bin or give it some heat. There are insulators made for bins. Tim hangs a lamp over the bin and sets a timer so the lamp warms the bin at night. Even if production slows, the worms are warm enough, and the food does not freeze.

worm-bin-under-light
Tim keeps the worm bin inside the garage with a light on a timer for winter warmth.

You’ll have more success if you break the food scraps into manageable sizes, about the size you get when running a peeler over a carrot.

Be sure to check instructions for worm type. Red wigglers (Elsenia festida) eat and reproduce better than most, but you can use European nightcrawlers (E. Hortensis), which work well in our tower.

harvesting-worm-castings
Once he emptied this layer of worm castings, he placed the empty tray on the bottom of the bin.

Store your worm castings in an airtight container and they’ll continue to break down. Just let the castings dry a little before sealing. They can be damp but not wet.

The leachate, or liquid that runs down, can be toxic. Don‘t use it if it smells bad or on edibles. Be sure to dilute it with a ratio of about 10 parts water to one part leachate.

If you’re looking for a way to get kids involved in gardening, worms are it! What fun kids can have helping care for the worms and seeing how they help a family grow food or pretty flowers for mom. It’s also a great way to teach responsibility if kids are charged with prepping scraps or bedding and feeding worms.

sifting-compost-worms
We returned worms still in the castings tray to the food tray and sifted out large bits of food or paper, leaving a rich compost.

If you can’t spend the money on a worm bin or tower, you can find information on making your own or vermicomposting directly into a garden bed.