Can Strong Scents In The Soil Really Help Prevent Gopher Damage?

Gophers are cute until you have to share your backyard with them. Despite being labeled as a pest, they are helpful for the overall environment since their digging can stir up nutrients in the soil and beneficial microbes. But on the downside, they can also pull entire plants below ground to eat them. So you may understandably be annoyed at gophers destroying your garden.

If you want to get rid of gophers humanely, you may be familiar with the idea of using scent to deter them. Gophers have a strong sense of smell, so in theory, an unpleasant smell could be intense enough to get them to move along. Anecdotally, some people have had success with pouring fish oil emulsion or castor oil into their burrows. They probe the ground for tunnels with something like a pool cue, and once the probe falls through, they insert a funnel and pour in the source of stink. Problem solved... right? Unfortunately, no. Despite the popularity of trying to deter gophers with a strong odor, there is no scientific evidence to support the efficacy of this method.

The problem with finding a scent that would deter all gophers is that there are so many varieties of the rodent. There are nearly 40 species of pocket gopher in North and South America. Attempts to study which scents kept them away found that effectiveness varies among species and sexes.  So, what works on a male gopher of one species may be useless at repelling a female gopher of another kind. 

Though a couple studies found predator odors to be effective, synthetic predator odors are not a consistent deterrent since gophers will just plug the section of the burrow that smells dangerous and move into another space. And since a single tunnel system can span up to 200 yards, they have plenty of places to go. The smells also dissipate quickly, so you would need to constantly apply and re-apply.

Predator scents work best if the gopher is removed from the burrow first, but even then, it is not consistent. The good news is that you are likely only dealing with one gopher at a time. Thanks to their territorial and antisocial tendencies, there is typically only one pocket gopher per burrow, unless you have a female raising a litter. The bad news is that gophers rarely leave their burrows, so good luck waiting for it to leave your yard.

Unfortunately, some other commonly suggested gopher repellants also have no scientific backing – sonic devices and products that promise to scare gophers away have not been proven effective. You should also never use capsaicin to deter gophers. A more effective method to remove gophers would be trapping. Though some traps can kill the rodents, there are live traps available that allow you to release them safely.

Ultimately, the best method to keep pests off your property is prevention. Protect your plants from underground with a gopher basket, making sure to leave at least 3 inches above ground so the animals cannot dig in from the surface. Even if gophers can nibble on the roots growing outside the basket, the main root system should be safe. You can also use raised beds protected with welded wire on the bottom, and sandier soils discourage burrowing even more. Besides plants, gophers can also damage underground cables. To prevent this, lay gravel around them and enclose buried cables in materials that boost their diameter to over 2.9 inches so they will be too big to chew.