by Learning Lead – Melinda Munding

Well, the worms have done their job digesting our food waste and breaking it down into nutritionally dense waste of their own, called castings, and now it is time to harvest those castings. Luckily, unlike other animal manure, worm castings have no offending smell at all. One of my favourite aspects of the Red Spruce Farm vermihut is the ease at which it allows worm castings to be harvested for our plants and gardens. In my previous single bin setup, harvesting time was a bit of a trickier task, as it required me to a) sift out the worms b) sift out the baby worms and c) sift out the leftover food waste and big paper strips. The single bin system was also prone to mold growth- not necessarily a problem, but not ideal for using on indoor plants. With the stacked vermihut, the worms migrate from one bin to another, and by the time they reach the top bin the bottom bin is ready to be harvested and no (or little sifting is needed). Most importantly, I do not need to be worried about accidentally transplanting worms.

Pascal is checking on the worms in one of the bins of the vermihut. After one month of feeding the worms in the bottom, we add food waste to the next bin up (melon rinds are a favourite of the worms and therefore, very attractive). Photo by Melinda Munding.

I used to have a very limited amount of worm castings when I was working with a single bin system and therefore, I had not considered too deeply about how the proportions of castings to use. Now that we have two very efficient towers, we have a significant increase in the number of castings we have and I began to ponder how much I should be adding to houseplants and garden beds. Steve, from the Urban Worm Company, did some pretty in-depth research into effective proportions in different types of gardens and had a helpful takeaway; even if you are working with a limited amount of vermicompost, you can have success. Studies have shown that a ration as small as five percent vermicompost can help plants grow stronger and more abundantly (Churchill). Interestingly, the ratios for increasing the yield of crops varies significantly from genus to genus of plants. For example, spice plants fared better with high rations of vermicompost (50%), while vegetable plants fared better with significantly less (5-10% vermicompost). Another helpful tip that I found helpful, is that vermicompost can continue to provide nutrients, and benefit soil and plants for years after one’s initial application (Churchill). Before reading this article, I had mixed some of the worm castings into my soil for growing a ginger plant and did not measure the proportion and had success!

Our ginger plant is grown with a mix of soil and vermicompost. Photo by Melinda Munding.

The last part of my acquired knowledge which I wanted to share with you, is about vermicompost tea. I used to believe that vermicompost tea was simply the leachate that occurs from the food waste and digested food. Now I know that vermicompost tea is actually made very much like an ordinary tea that one would drink.

The “tea” on vermicompost tea. Photo by Melinda Munding.

To make vermicompost tea, one puts a few tablespoons of vermicompost into a cheesecloth (or similar tool like a paper tea bag or paper coffee filter), then puts it into about four litres of water. Leave it to sit overnight (or longer) and then your tea will be ready to use. You can put the leftover compost back into your garden and use the vermicompost tea to water your plants. Using vermicompost tea is one more way to add nutrients back into soil if it is overworked, or to ensure that it remains healthy if it already is. Please note: this tea is effective for gardens and not meant for human consumption.

Works Cited

Churchill, Steve. “How Much Vermicompost Should I Use?” Urban Worm Company, 6 November 2014, Accessed 10 March 2022.

Vanderlinden, Colleen. “How to Make Vermicompost Tea.” The Spruce, 17 July 2019, Accessed 11 March 2022.