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Planning a Viable Kitchen-to-farm Bokashi Operation is all about Scale-to-context

Empty bokashi container drums in storage at the hotel’s Loading Bay area (left) and 500 liters of full drums at Soil Trust (泥玩)​​ farm waiting to be hot-composted (right).

SoilFeeder sets a model for bokashi-powered farming at scale. As outlined in earlier posts, bokashi is a simple process because it doesn’t need to be turned: you shred the fresh food trimmings, pack them into the container, push out the air and seal it. This way a small farm can generate enough stabilised organic matter as input for high-quality compost that is sufficient in volume to actually become independent from any external fertilizer inputs (‘nutrient autonomy’, as we call it). Soil Trust’s inspirational system can be very doable for other small to mid-sized farms as well. The key is to keep the bokashi processing on a human scale and suitable to the local characteristics.

Small-scale farmers in Hong Kong (and elsewhere) can be challenged to create enough horticultural compost from locally sourced organic material when they cannot use a motor vehicle for transportation. Farm access can be unpassable for tractors or there is a lack of resources. Yet, a thermi-compost pile requires stockpiling of at least one cubic meter (1000 liters) of organic matter to properly heat up. Soil Trust uses a narrow-track forklift and E-vehicle that can carry in one go up to 10 bokashi container drums (holding 50 liters each). This way 500 liters of bokashi food waste from the hotel are transported once a month to the farm. Together with an equal amount of wood mulch (500 liters) is the make-up of a balanced hot compost pile.

The monthly bokashi delivery of about 500 kg of organic matter must pass in the last several meters between the truck-accessible road and the Soil Trust farm through a narrow trailway.

Soil Trust’s workforce consists of one full-time farm manager and a dozen weekly community gardeners. The limited capacities of its team in combination with the actual biofertiliser demand of its 0.1 acres (0.05 hectares) small acreage dictate how much hotel food trimmings are accepted processed every month. Since the hotel generates about 500 liters of food waste in just two days, it could easily satisfy the organic matter needs of 15 farms like Soil Trust. The distance between the hotel and Soil Trust is 35 km, thus the bokashi pickup takes place monthly to reduce the transportation footprint.

Soil Trust has set the weight limit of its drum containers to 50 kg because they are hauled manually from the truck pallet to the hand trolleys. If circumstances require, two or even one person can safely manage this weight. Another ergonomic measure was to paint marks for bokashi layering inside the drum containers to guide the kitchen staff in packing the food trimmings with the bedding culture.

Container drums with bokashi layering marks (white stripes) that help hotel staff to sandwich food trimmings with adequate layers of bedding culture.

In addition to the SoilFeeders program, Soil Trust also collects bokashi-fermented food waste from 15 family households associated with a Community-Supported Agriculture (CSA) platform that amounts to not more than 150 litres per month. Being insufficient for regular hot-composting, the CSA’s domestic bokashi is used as direct soil amendment and will be used soon as feedstock in vermiculture.

Increasingly, smallholders worldwide are hesitant to use commercial compost or fertilisers and start collecting local residential or industrial food residues for controlling the biological integrity of their soil and animal feeds. Granted that the distance between the farm and kitchens is short then weekly collection models become plausible. An illustrative example is the regenerative flower farm that fertilises and feeds its 3 acres (1.2 hectares) three-person family operation entirely with homegrown bokashi compost. Here unprocessed food waste is collected in pails (for a small nominal fee) from its 100 CSA households every week and processed into 500 liters of bokashi centrally on the farm. No matter what the collection model is, the scaling of all kitchen-to-farm bokashi operations starts with the question of what the regenerative purpose of the bokashi is aimed at and what scale makes the most sense operationally to the agriculturist.

Keywords: kitchen-side processing, farm-side processing, supply/demand coordination, pail pickup, transport footprint, small equipment farming.


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