Granite Geek: What's The Best Way To Keep Deer Out Of Your Garden?

Jul 14, 2015

It’s July, and if you’re a gardener, that means little green tomatoes are popping up on your plants, flowers are attracting bees, and fruit trees are filling up with the beginnings of what we’ll harvest this fall. It’s also a time for deer to come by and steal a snack from your garden. David Brooks, a columnist for the Nashua Telegraph and writer at GraniteGeek.org, spoke with NHPR's Peter Biello about ways to prevent those deer from literally stealing the fruits of your labor.

What is the thing that keeps deer away?

Where there really sort of is nothing - at least there's no magic bullet. What I was actually looking for was a spray. If you go to your hardware store you'll see there's 5,6,7,8...10 different brands of sprays or granules that are supposed to keep away deer and sometimes other animals as well.

Do these sprays frighten the deer or smell so bad that the deer don't want to be there?

They repel the deer - there's two different ways that were explained to me, a fear repellent or a taste repellent. The fear repellent generally releases a sulfur because that is released by the feces and urine of meat-eating animals, so when deer smell it, they assume there's been a meat-eating animal around so they don't want to stick around themselves.

And the taste repellent is cayenne pepper or something that the deer don't like, so they have to lick that to be effective. Sometimes they're combined in various formulations.

What are the downsides to using repellents?

You have to apply them regularly, they can be washed away by the rain, they degrade in sunlight. If they're really good they might stink so much that YOU can smell the rotten egg smell (many of these are actually MADE from rotten eggs!) 

Many of them are not recommended to be used on food crops, so you can't really spray them on your green beans. And frankly, as both biologists explained to me, it's a function of what's happening around you. So if there's lots of deer around and there isn't much wild food in the woods, then the deer will have more incentive to eat your stuff. But it's a biological system and bioligical systems are always complicated, and you can't expect any straightforward answers.

And apparently if you find a spray that works well, it may not always work well?

That was the other thing they said that kind of surprised me, that by far the thing to do is rotate the repellents. The deer get acclimated to something, so if there's a spray you put on one year and they smell it and run away but maybe notice that nothing bad happened, the next year they may say,"what the heck, it didn't bother me last year - I guess I'll go through it." 

So you should actually try a variety of types and sort of mix and match. Knowing that if the circumstances are against you, it won't be enough.

And then you can go to more extreme measures.

Which are?

Well, they range from hanging bars of soap on your trees - for some reason, if they're really scented the deer don't like that - to lights that are motion activated, to radio playing all night, but even that one animals can get used to. But really, the only really effective thing to do is to fence them out. 

But, you know, if you're trying to keep them off of your pretty flowers in front of your house, you really don't want to build that six-foot electric fence in front of it. But if you have something you really want to protect, like my peach trees or something, I've never built a fence around it but if I really wanted to make sure I keep them that's what I'd have to do.

And what about just planting stuff that deer don't like to eat?

There isn't very much they don't like to eat or that they won't eat, if push comes to shove. I was told the only thing that's a sure-fire 'deer won't eat it' plant is garlic. Deer can be a real problem; their overpopulation here in the woods is a real problem. They eat all the understory and can really alter the entire ecosystem. If you go into a place that's been wiped out by a deer, though, there's still wild garlic growing.