Is Horse Manure Safe For Organic Gardens?

Vermicides kill intestinal worms, but are they also fatal to earthworms? Do vermicide toxins build up in the soil over time? Can vegetables be considered ‘organically grown’ if they were fertilized with vermicide-laced horse manure?


Fortunately for gardeners and animal owners, most research to date indicates that Ivermectin, the vermicide most frequently given to horses, cattle and sheep, breaks down quickly once it is excreted. Several studies have shown that Ivermectin degrades rapidly when manure is hot-composted or exposed to sunlight, and somewhat less rapidly when manure is simply piled up and left to decompose.

We’ll be picking up manure from neighbors with a couple of horses and we’ll expose it to sunshine for a while.