Christophe's Compost Corner Update from Frog Hollow Farm: Sept. 19, 2014

  • We have finished spreading our last windrow (S-42) which was started in June of this year. Most of this compost (about tons) was spread in the orchard because it is highly fungal. A portion of this compost (about 5 tons) was set aside and will be applied in the new vegetable block. However, vegetables grow in soil that is dominated by bacteria (the fungal to bacterial biomass ratio is less than one) and so the compost that is added has to be dominated by bacteria. Earlier this week, compost tea (highly bacterial) was added to 5 tons of S-42. This week-end the fungal to bacterial ratio of this compost will be analyzed.
  • Another windrow (S-43; about 66 tons) started in July is ready for spreading in the orchard as of today. We have two more windrows which were also started in July and they will probably be ready for spreading next week.
  • Marlene, the assistant farmer, is setting up a new vegetable block. One of the concerns that arises is whether the compost to be used as an amendment is free of plant pathogens and weed seeds. Another concern is the condition of the soil in a new patch: are any fungal diseases that may have occurred in the previous growing season still present in the soil?
  • Compost produced by thermophilic methods (aerobic, temperature control, watering) is free of plant pathogens and weed seeds. At Frog Hollow we monitor all aspects of compost production and consequently our composting operation is well managed. We know what materials go into our composting windrows: if something is suspect or smells bad it is removed (smell test). We closely monitor the temperatures of the windrows: we make sure that all parts of a windrow (by way of thorough mixing using a mechanical turner) reach a temperature of 130 F or more for a specified amount of time. Finally when the windrows have reached the end of their ‘life-cycle” (stability-maturity), we check the biology to make sure all microbes are in balance, which is an indication of a healthy compost.
  • Most if not all diseases of fungal origin are killed in a well managed thermophilic composting process (based on research data). Commercially produced compost is not always well managed and its origins should be carefully scrutinized. If some plant disease causes concern, it should be identified and the life cycle should be investigated (in the scientific literature). The mechanisms by which compost suppresses or kills plant pathogens is probably a combination of high heat, aerobic conditions and competition between beneficial and pathogenic organisms for food resources in the compost windrow.
  • We will discuss in the next blog how vermicompost is managed and how plant pathogens are removed or reduced.
  • Two weeks ago, Nocci, Becky’s farm dog, died in a car accident. She was a sweet and friendly dog that everybody liked. When the next compost windrow is constructed, it will be labeled Nocci-1 (N-1) in memory. Presently the windrows are labeled S for Sittler (brand name of the mechanical turner) because the turner help us improve the management of our composting operation.

Author: Christophe Kreis MLF Soil Consulting PhD, Molecular Biology/Developmental Biology, University of British Columbia, Canada. Christophe is co-founder of MLF Soil Consulting with his wife Monique. He started his career in basic medical research and after various positions in academia and industry Christophe slowly returned to his first passion Soil Ecology and Microbiology. It is his belief that human health is tied intimately to soil health through the production of healthy food. For this reason MLF Soil Consulting is committed to help farmers improve the management of their soil through composting, vermicomposting and biological analysis of microbial soil life.

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