A couple of weeks ago, we moved piping hot compost into the greenhouse. The greenhouse at the Four Winds Farm is not heated with electricity or fossil fuels. In February of each year, two dump truck loads of unfinished compost are moved into one of the brick walls of the greenhouse. The brick walls are covered with wooden palates and become the benches that the seedlings live on until they are transferred outside in May. The micro-organisms present in the composting mass produce heat as they digest organic matter. In the Spring, as the greenhouse fills with temperature sensitive seedlings, the composting process produces enough heat the keep the greenhouse at ideal seed starting and seedling growing temperatures. In addition, the compost moved in from the previous year is screened into a fine soil and used for all our potting needs, from vegetable starts to seedlings for the annual Four Winds Farm Seedling Sale.
The raw materials for the compost are a mixture of organic matter and animal manure. The bulk of the compost comes from a nearby horse farm. Horse farms regularly clean out the stalls for the horses, leaving them with a mass of bedding filled with manure and urine. The piles of horse bedding are considered a water pollutant, and therefore the the horse farms are required to remove them from the premises. Instead of shipping them off to a landfill, many farms in our area pick up loads of this waste material and turn it into a valuable resource. After a year of composting, the horse bedding turns into a rich source of nutrients for plants. Animal manure lets off ammonia during the compost process, which is actually toxic to plants in an enclosed area. This issue is easily remedied in the greenhouse by adding a thick layer of year old, finished compost to the surface, which acts as a filter for the sensitive seedlings.
Of course, forgoing fossil fuels to heat the greenhouse takes a lot of man power. We moved the compost into the greenhouse with pitchforks and wheelbarrows. For me, this work is like the annual rite of passage into the growing season. We all put our winter selves into a day of tough work, which inspires us for the work load ahead.