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✕Avoid
Mothballs, soap and human hair as repellents
Folklore, with the added problem that one of them is an illegal pesticide application.
What it is
Scattering mothballs, hanging soap bars, or spreading human or dog hair around a garden to repel deer and rodents.
The numbers
- Mothballs are a registered pesticide, and the label is the law. The label says to use them in a sealed container with fabric. It does not say 'scatter in garden' — outdoor use is a misuse, and the naphthalene or paradichlorobenzene leaches into your soil and groundwater.
- Soap and hair show weak, short-lived and inconsistent effects in testing, mostly on the order of days.
- Predator urine as a perimeter is similarly weak and inconsistent, expensive, and washed off by the first rain.
- Anything scent-based fails the same way: the animal learns the smell predicts nothing.
Why it's here
Because these are the most-repeated garden tips that have never produced a number, and they crowd out the two things that work — a fence, and the motion sprinkler.
The catch
No catch to manage; they just don't hold up. If you want a scent-based tool that does have evidence behind it, use an egg-solid repellent and accept that you'll be reapplying it. If you want the problem to stop, build the barrier.