Manure Compost & Plant Viruses in a Vegetable Garden

Although manure is an effective fertilizer, it must be properly managed to prevent diseases in your garden. However, with the proper care, the use of manure can help your garden thrive.

Identification

Since cows and horses are herbivores, diseases and pathogens that are present in plants may be passed in a living state in their manure. In most cases the heat generated in composting the manure will kill these pathogens; but if not properly managed they can persist.

Types

Pathogens found in manure include verticillium wilt, blight and E. coli. Although E. coli does not affect plants, it can be potentially fatal if you or your family eat vegetables contaminated with it.

Prevention/Solution

Temperature is key to killing off pathogens in manure. Temperatures must be kept at 131 degrees F or more for 15 days or longer to properly kill off disease-causing pathogens. The manure must be turned so that all parts are exposed to these high temperatures for at least three days. You can buy manure already composted, but it will be more expensive than fresh manure.

Fresh vs. Composted

Since fresh manure has high levels of nitrogen, it can actually burn your plants. When composted, the minerals in manure become more balanced and can increase the nutrient content in your soil.

References

• University of Minnesota: Using Manure and Compost as Nutrient Sources for Fruit and Vegetable Crops
• Washington State University: A Guide to Composting Horse Manure
• University of California: Pathogens in Manure