Our Approach to
Sustainable Growing
At Windmill Farms, sustainability is built into how we grow, manage resources, and return value to agriculture. From vertical growing systems and circular compost use to water treatment and energy recovery, our operations are designed to support efficiency, reduce environmental impact, and help protect the natural resources our future depends on
Inside Windmill’s Operations
Inside Windmill’s Operations
Built for Quality & Consistency
Vertical Farming at
Windmill Farms
Windmill Farms grows mushrooms in a controlled indoor environment using vertically stacked growing systems that enable efficient, year-round production. This approach makes effective use of space within the facility while allowing key growing conditions such as temperature, humidity, and airflow to be carefully managed throughout the crop cycle. The result is a consistent growing environment designed for reliable production at scale.
Built for Quality & Consistency
Vertical Farming at
Windmill Farms
Windmill Farms grows mushrooms in a controlled indoor environment using vertically stacked growing systems that enable efficient, year-round production. This approach makes effective use of space within the facility while allowing key growing conditions such as temperature, humidity, and airflow to be carefully managed throughout the crop cycle. The result is a consistent growing environment designed for reliable production at scale.
Controlled environment
Growing conditions are managed indoors year-round
Vertical growing
Stacked systems maximize production within the facility footprint
Efficient use of space
Helps support high-density mushroom production
Year-round production
Indoor operations support consistent growing conditions
A Circular System
That Starts & Ends
on the Farm
Windmill Farms is part of a circular agricultural system in which materials are used beyond a single growing cycle. Compost made from farm-sourced ingredients supports mushroom production, and once it has been used, the spent compost is returned to agricultural partners where it is applied to fields, incorporated into soil blends, or used to improve overall soil quality. This creates a practical loop between mushroom production and agriculture, helping valuable organic material stay in use.
Farm-sourced inputs
Compost ingredients are sourced from North American farms
OMF Compost
Compost is prepared to support mushroom growing at Windmill Farms
Mushroom production
The substrate is used in growing rooms across the facility
Spent compost
Material is removed from the growing rooms after use
Returned to local agriculture
Spent compost is distributed to partners for field use or soil blends
Back to the land
Organic matter and nutrients are returned to the land, improving soil quality
Farm-sourced inputs
Compost ingredients are sourced from North American farms
OMF Compost
Compost is prepared to support mushroom growing at Windmill Farms
Mushroom production
The substrate is used in growing rooms across the facility
Spent compost
Material is removed from the growing rooms after use
Returned to local agriculture
Spent compost is distributed to partners for field use or soil blends
Back to the land
Organic matter and nutrients are returned to the land, improving soil quality
Where Compost Gives Back
Returning Value to the Soil
Spent compost provides value beyond the growing room as a useful soil amendment for agricultural applications. Its high organic matter content helps improve soil structure and retain nutrients, while peat moss in the material supports water retention. It also contributes nutrients such as nitrogen, phosphorus, potassium, and magnesium, making it a practical input for soil improvement. Because it comes from indoor facilities, it is also essentially weed-free.
about OMF Compost
OMF Compost is the only fully enclosed organic composting facility of its kind in North America. It supports both Ashburn and Manchester production by producing the substrate used in Windmill’s growing process. Using ingredients sourced from North American farms, OMF provides a critical input into mushroom production and helps support the broader agricultural cycle connected to Windmill Farms.
Over 100M lb
of spent compost returned to local farms in 2025
100%
of spent compost is distributed among partners
Water retention
Peat moss in the material helps hold moisture
Nutrient value
Provides nitrogen, phosphorus, potassium, and magnesium
Weed-free
as it comes from indoor growing facilities
Water Management &
Wastewater Treatment
Windmill Farms operates an on-site wetland water treatment system designed to reduce reliance on fresh water. Wash water from across the facility, including water used to clean the building and equipment, is collected and directed through a system of filtration, treatment, and storage before being reused in cleaning operations. Surplus treated water is returned to the ground through a subsurface infiltration field. In partnership with Rivercourt Engineering, Windmill Farms regularly reviews system performance, monitors water quality, and works alongside environmental regulators to ensure the system continues to operate as intended, while continuously exploring new ways to expand the use of treated water throughout the facility.
The system helps conserve fresh water by reusing treated wash water in building cleaning operations
≈ 6,000 litres of treated water are reused every day
Regular water samples are analyzed and reviewed in conjunction with MECP requirements
Hall Heating System
Windmill Farms uses a heat recovery system in two facility corridors, designed with efficiency in mind. It uses heat from the growing room cooling system to warm working hallways during the winter months, helping keep these areas above freezing while also cooling the glycol used in growing room operations when cooling is required. This reduces the need for separate heating and supports more efficient energy use across the facility.
42,000 ft²
of corridor space is heated by this system
Winter temperature support
Keeps working hallways above freezing in winter
Heat recovery in action
Reduces the need for separate heating
Smart Systems at Work
Growing Room Cooling & Heat Recovery
Windmill Farms uses heat recovery and free cooling systems to support efficient temperature management in its growing rooms. Each growing room is equipped with a large thermal heat exchanger that helps precondition incoming fresh air used to control growing conditions during cropping. In summer, cold energy is taken from exhaust air to pre-cool incoming air. In winter, heat from exhaust air is used to warm it. During colder months, free cooling chillers use low outdoor temperatures to cool glycol, reducing reliance on mechanical refrigeration.
Thermal heat exchangers help recover energy in both summer and winter
of growing rooms at the Manchester facility use this system
of Canadian production facilities use this system
Free cooling chillers operate in winter, when outdoor temperatures are 0°C or below
Quality, Carefully Managed
Environmental Controls
Fancom environmental control systems are used to monitor and manage growing room conditions throughout the mushroom growing process. These systems help regulate air temperature, compost temperature, relative humidity, carbon dioxide, and fan speed, supporting consistent growing conditions across Windmill’s facilities.
100% of growing rooms
Use Fancom environmental control system
Temperature monitoring
Tracks both air and compost temperature
Climate regulation
Helps manage humidity, carbon dioxide, and fan speed
Quality, Carefully Managed
Environmental Controls
Fancom environmental control systems are used to monitor and manage growing room conditions throughout the mushroom growing process. These systems help regulate air temperature, compost temperature, relative humidity, carbon dioxide, and fan speed, supporting consistent growing conditions across Windmill’s facilities.
100% of growing rooms
Use Fancom environmental control system
Temperature monitoring
Tracks both air and compost temperature
Climate regulation
Helps manage humidity, carbon dioxide, and fan speed