No-turn composting using the SPICE method
Thank you for the ‘internduction’ Urban Kai Farms!
As pointed out I am the compost intern. I’ve become a big fan of compost over the years, and with my background in nutrition how could I not be. Its ability to nourish soil just from combining run-of-the-mill items such as food scraps, grass clippings, cardboard etc. to this very day amazes me.
Composting is a form of waste disposal where organic waste decomposes or breaks down naturally by earthworms, bacteria and other organisms that live in soil.
Sometimes carrying compost is a two person job
One of the biggest things I’ve learned to date is that composting can add more carbon to soils. When soils are rich in carbon they behave like a sponge; soaking up water and nutrients that are then gradually released for plants to use. Plants become healthier, nutrient dense and resistant to any pests and diseases; benefiting the waiora of our environment and our human health.
Urban Kai Farms have been working on a few composting methods over the years, particularly vermicomposting at the ReMakery and Epuni school; open and covered composting piles at Riverside; and up until recently Static Pile Inoculated Compost Extension aka ‘SPICE’.
‘SPICE - also known as fermentative composting is a low cost and easy method for effectively composting at a large and small scale.’ - Gerry Gillespie, Returning Organics to Soil
And would you believe it no turning is required! These windrow shaped compost piles are instead inoculated with beneficial microorganisms designed to breakdown organic matter with little to no oxygen. Because the compost pile has to be covered for this fermentation process to occur there is hardly any odour. No-turn covered composting also means more carbon can be kept in the compost; ensuring a nutrient rich product. It’s a win-win.
The key steps to making compost using the SPICE method are:
Making the SPICE inoculant. Check out this factsheet with the two part recipe from NutriSoil. (Note this recipe makes 200 litres, and can be made using a 200 litre blue barrel as seen pictured below).
SPICE inoculant aka ‘witcher’s brew’ (analogy courtesy of Roy).
2. Prepare bed and source materials. We used what was readily available such as grass clippings, wood chips, malt from the local brewery, coffee husks, egg cartons, dried summer crops such as beanstalks, brassicas etc. Similar to traditional compost pile methods we aimed for around a 25-50:1 ratio (carbon to nitrogen).
Adding materials such as egg cartons, brassicas, woodchip etc.
3. Layer, wet and inoculate materials. We layered material using the traditional open pile composting method and watered each layer as we went along ensuring any hand squeezed material produced a few water drops. We diluted 1 litre of inoculant with 10 litres of water and applied every 2-3 layers using a watering can. This ratio of inoculant can also be used as a foliar or soil stimulant which we used on the ‘too many tomatoes’ :).
(N.B if possible mix, water and inoculate materials first before building the windrow especially if using this method on a larger scale. Aim to use 1 litre of inoculant for every 10 cubic metres. It is also preferable to use non-chlorinated water if possible).
Hannah distributing grass clippings; Pam on the end of the hose watering the materials
4. Cover compost. The minimum time to keep the compost covered is 4-6 weeks. We used a vinyl billboard ‘skin’ (can use any UV stabilised tarp) and weighed down the tarp using old tyres and timber. We also created a small dent on top to allow moisture to drip down and cycle into the pile.
Making a small dent on top of the compost allows moisture to drip down and cycle into the pile.
5. Monitor composting process. In 1-2 days the temperature can climb to around 65 - 70 degrees °C and then fall back to around 50 – 55 degrees °C. While ensuring the temperature stays within this range, we were on the lookout for any grey powdery flakes and filaments called ray fungi or actinomyces (these are actually bacteria) that can be observed in piles. If these takeover however, the pile might be too dry, so we will apply more water as required.
Weighing down the tarp with tyres and timber
Looking forward to reporting back on how we get on over the next month when this composting process is complete! We can safely say we think the caulis and pumpkins on the periphery are definitely enjoying their new neighbour. We can’t get over how much they have grown in the last two weeks!