Is it safe to use manure on my vegetable garden?

ASK THE HORT AGENT

Question Is it safe to use manure on my vegetable garden?

Answer Yes and no. If you take a few precautions, then you should be fine. Farmers have been doing it for hundreds of years. If you get sick, then I told you not to.

Pathogens (microorganisms which cause disease) can be transferred from animal manures to humans. The pathogens Salmonella, Listeria and E.coli ,as well as parasites, such as roundworms and tapeworms, can be found in the applications of manure made to gardens.

In August 1993, the Lancet Medical Journal reported on a small E.coli outbreak that appeared to be the result of manure applications to a garden. The gardener 's diet relied heavily on vegetables from her garden. She fertilized the garden all summer with manure from her cow and calf. E.coli bacteria was isolated from fecal samples taken from the cow and calf as well as the garden soil.

So, how risky is the use of manure in gardens and compost piles? If you use fresh manure in the garden, there is a risk that pathogens which cause disease may contaminate vegetables. The risk is greatest for root crops, like radishes and carrots, and leafy vegetables where the edible part touches the soil (lettuce). Careful washing and/or peeling will remove most of the pathogens responsible for the disease. Thorough cooking is even more effective.

The process of composting (actually decomposing) significantly reduces the populations of diseases and parasites. Aging (letting it sit around) will also serve this purpose. To further reduce the risk of disease, follow these precautions. Apply fresh manure at least 60 days before harvesting any vegetables which will be eaten without cooking. Within 60 days of harvest, use only aged or composted manure. Never apply fresh manure after the garden has been planted. Thoroughly wash raw vegetables before eating. Do not use cat, dog or pig manure in gardens or compost piles, because some of the parasites which can be found in these manures may survive and remain infectious to people.

People who are especially susceptible to food borne illnesses should avoid eating uncooked vegetables from manured gardens. Those who face special risks from food borne illness include pregnant women, very young children, and persons with chronic diseases, such as cancer, kidney failure, liver disease, or diabetes.

Fresh manure also has a way of making your vegetables smell like ... manure. For more info on using manure, visit http://www.hort.wisc.edu/mastergardener/features/misc/manure/manure.htm If you don’t have internet access or have other stinking questions, call me at 910-893-7533 or email me at gpierce@harnett.org

Warning – if you plant vegetables over your septic drain field, then they may taste like a mix of a shot of scotch stirred with a peat moss teabag. Oh wait, scotch already tastes like it was stirred with a peat moss teabag.

Gary L. Pierce

Horticulture Extension Agent

Harnett County