Access to proper space, water, sunlight, fresh air and healthy soil can make growing food in cities very challenging. Urban farmers must therefore use innovative ways to maximize a city’s growing potential. Healthy soil plays a vital role in this issue, but is increasingly under threat from degradation, pollution and development. Container rooftop gardens have become a popular way to grow in the city, but requires the proper soil mix.
This blog focuses on the soil building practices that we use to grow some of our ingredients at ChocoSol. 2015 has been declared “Year of the Soils” by the United Nations so it’s a great opportunity to highlight how we are composting our kitchen scraps into high quality “ChocoSoil” with help from our worms!
We process the food and garden scraps, paper towel, cacao shells and coffee grinds using red wiggler worms (Eisenia fetida). This “vermicomposting” process produces nutrient dense worm castings. All compost is considered humus, a crucial ingredient for any soil mix. Not only does humus help with water retention for our soil, it provides our plants with nutrients and essential soil microbes, plus protects them from pathogens and harmful bacteria.
Vermicomposting fits under the “cradle to cradle” approach of handling waste at our facility. Cradle to cradle mimics nature’s efficient and waste free cycles, whereby our organics are not wasted but are processed back into compost and returned into our garden soil. We believe that this approach is essential to tackling Toronto’s waste issues. In 2014 alone our city produced 380,552 tonnes of waste, approximately half of which is organic material. Once landfilled the organics breakdown and produce methane, a significant greenhouse gas.
To set up a vermicomposting unit at home, remember that it is important to create a comfortable environment for your worms. Our system consists of 6 large plastic tubs with holes drilled into the sides and tops to ensure air flow. The bins are also kept in the shade to avoid overheating and drying out. According to Mary Applehof, self-described “Worm Woman” and author of Worms Eat My Garbage(1982), the ideal temperature for your bin is anywhere between 15-25°C., but they can survive in temperatures as low as 0°C and as high as 30°C. Make room inside and outside to enjoy composting year round!
Your bins must also have a balanced carbon and nitrogen ratio. Our carbon sources are paper towels, coffee cups and corn stalks, which also acts as an essential bedding layer to block light and fruit flies. Our nitrogen sources are the kitchen scraps and coffee grinds.
Ensure the worms stay happy by checking the temperature, moisture, acidity (pH levels), amount of food and airflow within your bin on a weekly basis. Managing our project takes a small dedicated team (hi!), but most single-family vermicomposting systems take little maintenance since food can be added on a semi-regular basis.
Worm bins are just one of MANY great composting options – it works best for us because it’s relatively quick and doesn’t take up a lot of space. We process approximately 15 pounds of organic waste each week and since April we have harvested over 130 pounds of castings!
Please tweet us your pics and stories of your own composting adventures (@chocosoltraders) with the hashtag #worms4all. If you have any questions about starting your own worm composting unit please email us! We can direct you to some great resources or give you some pointers from our own experiences.