Wednesday, November 26, 2008

Greenhouse and Nursery - Heat from Compost

In the composting process, heat is generated and piles can go well over 150 F. If a portion of the heat can be captured from this process, you could use it to heat greenhouses and nursery production houses. One organic grower in Delaware did this on a very small scale. The following is more information and my thoughts on the subject.
  • Kathy Brooks, an organic herb grower in Kent County, partially heated her small greenhouse using heat from a compost pile. She is offereing information on how she did this. Here is the information from Kathy: Due to the overwhelming response to the most recent article on my heating system in Farm Show magazine I created a shortened version of the book that I am writing so I could get it to those wanting information immediately. I am pleased to announce that it is now available. The black and white version sells for $10.00 and the color copy is $15.00 plus $2.00 shipping cost. I included construction details, pictures and information on avoiding problems. To order please send your check payable to: Kathy Brooks,7371 Canterbury Road, Felton, DE 19943. For those in the immediate area I will try to deliver them or meet at a convenient location to get them to you.
  • In Europe, market gardeners have for hundreds of years used the heat generated from decomposing straw and manure over beds to heat during cold months and grow food crops out of season. This "hot box" approach still can be used.
  • A greenhouse or nursery might consider the addition of a compost business and capture some of the heat during composting to heat production facilities. This would require some infrastructure with piping under or inside of compost piles, pumps, and heat distribution systems. It would also require adequate sizing of compost piles and having sufficient piles coming on at different times to have a constant source of heat. The materials used in the composting process is also an issue to generate enough heat.
  • One of the real potentials with this source of heat is to use it in bottom heating systems for greenhouses and nurseries where water is recirculated through the compost pile and back into the production facility.

Photos of the heating system using compost that Kathy Brooks used to heat her small greenhouse. Photos by Kathy Brooks, Misty Morning Herbs & More, Felton, DE. This same concept could be used on a larger scale for production greenhouses or nursery propagation facilities.

Gordon Johnson, Extension Agriculture Agent, UD, Kent County

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