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Our Farm-to-School Americorps Member Frank Dipietrapaul on how to engage children in science with worms.

Almost everyone I know has some childhood story about worms. Deep down we all love them, even if somewhere along the line we developed a misunderstanding. My first experience with worms is an account from my mother; I was about three, playing in the dirt when she handed me a worm from the front flowerbed to investigate. When she turned away to plant her next Vinca she heard some slurping and lip smacking. Yes that’s right, I ate it. I always promote healthy eating so maybe that was the seed of my back to the earth, whole foods eating habits right there. So how does this relate to vermicomposting anyway? Well, with the help of our soil dwelling friends, we can turn our food waste into food wealth. I suppose when I was three I decided to skip a few of the in between steps, so now I am going to break it down and show how easy and rewarding it can be to keep our own worms at home.

Vermicomposting is the process of using worms and associated microorganisms to turn food scraps

City High School Students Tending the Garden
Students from City High School, one of three CITY Center for Collaborative Learning schools, tending our garden at Las Milpitas Community Farm and learning about compost and soil.

into worm castings (worm poop). These castings are a black, nutrient dense and earthy smelling humus. Due to the abundance of humic acids and microorganisms, they are typically richer in most required plant nutrients than traditional compost; they also improve soil structure for any garden to which it is added.

The best worms for a worm bin are Eisenia fetida, or red wigglers. We use them in particular because they thrive in rotting vegetation, compost and manure. Also as an epigean, they are most active in the first few inches of soil, which is ideal for small, shallow at home worm bins. When you bury your kitchen scraps in the worm bin, the microorganisms immediately begin to break it down and soften it for our toothless friends, the worms (you can also make a smoothie for them so they can eat your scraps even faster). They crawl up to your rotting veggies to feed and so begins the digestive process that gives us our so called “black gold.” Don’t forget worms need to drink too, but only enough to moisten the soil, not drench it.

As these worm castings build we need to harvest them. Just as you would muck a stall for horses, we must occasionally scoop out that amazing worm poop. Using light is the best technique. Since worms are photosensitive they usually dive to avoid exposure to the sun. We can then slowly scrape off the poop in layers as they continue to dive away from the sun. Once the castings are harvested you will want to add new compost and coconut coir. It’s best to use a 50/50 mix of these two substances. The compost provides additional nutrients and the coir adds water retention properties.

Building one is a piece of cake. A plastic tote is the simplest method, typically costing less than $10. Drill some holes around the sides for air and some along the bottom for proper drainage and it’s ready for the bedding. Compost is very inexpensive and the resources available around Tucson oftentimes make it free. The coconut coir usually runs about $15 for a 10-lb brick, but you will need much less than this to start one worm bin. While coir is ideal, you can also use much cheaper or even free ingredients such as shredded paper, cardboard or other carbon-rich, “brown” materials. Mix these two components in the bin no more than 12-18 inches deep and make sure the mixture is about as wet as a wrung out sponge before you add your worms. The worms can be purchased for about $15 and you’ll have more than enough to begin. Again though, with community support the cost can be mostly negated. Share those worms! They breed naturally in the bins and you’ll be able to pass out worms at all your parties and potlucks. All in all, you shouldn’t expect to spend more than $20-$25 per worm bin, but luckily with the practice of worm composting spreading and a friendly community your only expense might be the bin itself.

Student and teacher farming at Las Milpitas.
City High School teacher, Jenn Knochel, and student learning the science of soil and how plants grow at Las Milpitas Community Farm.

As this is so cheap and easy to build and maintain it makes for the perfect classroom pet project. Students can feed them their leftovers once a week and perform an assortment of scientific experiments to make sure the worms are happy. Monitoring pH and measuring moisture and nitrogen levels are but a few to keep you busy. Not only are worms cheaper than a hamster, they usually smell better too, if properly maintained. Instead of spending money on food, why not use your own, while at the same time making your own valuable fertilizer for the school garden?

Frank is leading a workshop on composting at Las Milpitas Community Farm on Saturday, December 15th, 2018 from 9:00am to 12:00pm.  Click here to register.


“Worms Eat My Garbage: How to Set Up and Maintain a Worm Composting System” by Mary Appelhof

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