Compost Uses and Markets
Compost Uses and Markets: Expanding Opportunities
John Biernbaum
Department of Horticulture, Michigan State University
East Lansing, Michigan
Compostponics is making physically stable,biologically active and mineral balanced compost from local feedstock materialsfor the purpose of growing plants in raised beds and containersusing 100% compost.We can observe weeds or pumpkin vines or tomatoplantsgrow in a compost pile. Compost has been used as a growing media for urban agriculture for decades.Compost suitable for containerplantproduction can bemarketed direct to the end user or growing media producers.
Compostponics is based in part on the assumption that increasing the quality, value and price of compost willincreaseorganics recycling andthe economic viability of commercial composting.Commercial composting is more challenging in the Midwest US due to low landfill tipping fees compared to coastal US regions. Compostponics is based on10 years ofpriorresearch of peat-based container media for greenhouse production andthe following 20-years of research and experience working with organic farmers and gardeners to increase the use of compost as a soil amendmentfor healthy soil, a component of greenhouse container plant growing mediafor seedling transplants,and as a mediumfor container-grown plantsand urban agriculture.
Research testing of compost forcontainergrowing media over the last 40 years hastypicallybeen based on asking whether a particular compost will workas a component of growing mediaand at what rate of addition. The research needed instead is development ofa protocol for how to produce compostsuitableforuse asacontainergrowing mediabyeither blendingmultiple types of compostor the addition of fertility amendmentsprior to composting.Desired physical (air and water holding), chemical (pH, soluble salts, mineral balance) and biological (minimal plant disease, mineralizing and nitrifying bacteria) characteristics have been well defined for peat and bark based container growing media. Based on our research,the addition of calcium to balance cation minerals and sulfur to lower pH are beneficial. The protocol likely will include the blending of different types of composts(municipal, manure, food scrap, etc)varying in maturity, particle size and nutrient levels. Ramial wood chips or charcoal added at the start of composting can provide necessarystable particles foraeration. A very mature compost may have excess soluble minerals and low available carbon to maintain biological activity while an immature compost may have excess biological activity and low available nutrients; but a blend may provide the desired characteristics. We have also developed low cost methods for larger scale production of vermicompost to be blended into the growing media. Vermicompost can also be used as a nutrient addition during container plant production.
The topics covered in this presentation will includean introduction to:possible feedstocks, recipes, production methods including vermicomposting,maturity considerations,the importance of multiple types of organic matter for healthy soil,ideas related to blending composts,the impact ofparticle sizeand container height on aeration,current research on fertility additions andmethods of compost analysis