Oh, deer, don’t do that!
I recently received an email with a question I’d never thought about before.
Jim from Upper Providence Township wrote:
“I frequently have to pick up after the deer that pass through my yard and have been throwing the waste in my trash can. However, if I had to clean up after a cow, I assume I could use the waste in my garden. So, would it be okay to mix in the deer waste with my garden soil? If so, are there any guidelines to follow?”
Although there is a group of deer that visits our yard daily and leaves plenty of poop behind, I’d never thought of these “offerings” as potential fertilizer and had no idea if they’re safe to use around vegetables.
All I really knew is that deer — like cows, sheep, goats, moose, camels, deer, giraffes, and buffalo — are ruminants.
Ruminants feed on grass and other plants that contain hard-to-digest cellulose. They accomplish this through the action of a four-chambered stomach that aids in the breakdown of the cellulose, allowing the absorption of the food value of the plants.
Since deer are herbivores, my first thought was that of course deer waste could go into the garden.
I wanted to be sure, so I turned to the internet and quickly discovered that my assumption was wrong: deer waste in the garden can expose you to E. coli and the deer disease known as chronic wasting disease.
Investigating further, I found that while there’s a possibility of CWD being transferred to humans in this way, there is no citable evidence that it happens.
At veggiegardener.com I read that, “At this time, the possibility of fecal transmission from deer to human has not been determined and no human case of CWD is on record. Even so, deer waste is not something you want to allow to remain in your garden. Additionally, proper handling of deer feces should be done so that accidental contamination of one’s own body does not occur from an E. coli perspective if nothing else.”
I was surprised about the E. coli risk. I thought that it was spread only through the fecal matter of carnivores. That led me to wonder how safe it is to use the manures that have traditionally been used as fertilizer for crops.
Information on the Penn State Extension Service website states that “Cow, horse, chicken/poultry, sheep, goat, and llama manure are acceptable types of manure appropriate for use in vegetable gardens.”
They caution that dog, cat, and human waste should never be used in a vegetable garden.
But it turns out that care should be taken with any kind of raw animal “fertilizer.”
The website cites an article from the University of New Hampshire entitled Guidelines for Using Animal Manures and Manure-Based Composts in the Garden as follows: “To ensure that pathogens have been killed, the compost pile must reach a high temperature (between 113 and 140 degrees) for … several weeks. The compost must also be turned regularly and carefully monitored so that all the manure has been exposed to sufficient temperature. In home compost piles and in unmanaged manure piles, this rarely happens. Aged manure is not the same as composted manure and it is not safe to assume that pathogens in an aged manure pile have been destroyed.”
The Penn State website goes on to say, “In an effort to reduce health risks when using manure in home gardens, the USDA National Organic Program suggests waiting 120 days from application to harvest for edibles that grow in or touch the soil. For other crops, the recommended wait time is 90 days from application to harvest for these edibles.” https://extension.psu.edu/wise-useof-manure-in-home-vegetable-gardens
More excellent information is available at the University of Idaho Extension website, https://tinyurl.com/225wzbrm and at the University of Wisconsin extension website, https://tinyurl.com/mrczmu4y