Fresh manure is a safe, ready-to-use fertilizer you can spread straight onto the garden.
Fresh manure isn't a ready-to-use fertilizer. It can burn plants with ammonia and salts, and it can carry E. coli, Salmonella and Listeria. Leaving it in a pile doesn't reliably kill those; hot composting helps. Never put raw manure on growing food crops, and leave at least 120 days between raw manure and harvest for anything that touches the soil.
What is actually known
Fresh manure is not a ready-to-use fertilizer, for two separate reasons. It burns. Fresh manure is higher in ammonia and can be high in salts, which can burn roots and foliage, and weathering and rain reduce both. And it can carry human pathogens (Listeria, Salmonella and E. coli O157:H7), which aging does not reliably remove. Storing manure in a pile is not regarded as a reliable way to destroy them, though a compost pile that reaches 140 °F reduces the risk further. Raw manure should never go on growing food crops, and guidance puts at least 120 days between raw manure and harvest for crops that touch the soil, and 90 days for those that do not. Composting can concentrate salts, so even composted manure can be salty.
The evidence
Evidence: checked against 3 sources in the research-based literature.
The 3 sources
Animal manure can contain bacteria such as Listeria, Salmonella, and E. coli 0157:H7 , as well as roundworms and tapeworms
Storing manure in a pile will cause some death of disease-causing bacteria, but is not regarded as a reliable way to destroy them
Salt content may be high in fresh manure and decreases with exposure to rains and irrigation as salts are leached out
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Cite this page
Milpa Gardens. "Fresh manure is a safe, ready-to-use fertilizer you can spread straight onto the garden." Evidence grade: Refuted. https://milpa.garden/beliefs/fresh-manure-raw-manure/
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