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Saturday, April 10, 2010

Garden Defense -- Repelling Four-Legged (and Two-Winged) Pests, by Jason

Finally building a cabin in the woods close to nature can be a dream come true.  But if you are a gardener like me, the morning after the first midnight garden raid by pests unknown can be a real nightmare. 
Garden pests never attack the day after harvest or when the plants are young.  They always seem to attack my garden the day before the big haul.  A garden full of just ripened fruit and veggies must look like a neon all-you-can-eat sign to a hungry deer, or rabbit. 
There are ways to effectively turn that sign off but it will require perseverance and definitely some trial and error.
Deer
The most persevering four legged pests to ravage a garden are deer.  Their sheer size and appetite can make for absolute garden destruction.  Worse yet, many times they will simply ignore the things a gardener is apt to do to repel them.  They jump all but the very highest fence and eat right through a lot of treatments to plants.
Natural (or at least passive) repellents can be used but it is a lot like using a pesticide.  Eventually the pests develop immunity to the treatment.  Repellents are theorized to work in two ways.  The first way is by presenting the deer with something they associate with human activity.  Deer in most places have learned to avoid humans at all costs.
There are a few repellents that fit into this category.  The first is soap.  A technique taught to me by an old Kentucky corn farmer was to actually put the soap in a sock and hang it from a stretch of fence.  He hung them about every 40-50 yards.  When asked if they worked he replied, “for a little while, then the damn things lose their fear”.  Some people rub the soap onto a pie pan and hang it from a string close to the garden.  I’ve never tried this but it should work in about the same way.
The second human related repellant is a little more revolting to most people.  That repellant is urine.  Collected over a period of time and poured in a perimeter around the garden, this will sometimes keep the deer away.  Just be aware that urine in its raw state can burn your grass and crops.  The theory here is that some deer just associate the smell with humans or that they can discern the smell of the urine of a predator. 
Some people claim that human hair can also be used.  Probably also best placed in a sock and hung from a fence.
There are also many plants that can be companion planted in your garden to repel deer.  This second group of repellents works by odor as well.  This group works by masking other odors.  The theory with this group is either the deer won’t go into places where they aren’t able to smell predators due to the strong scents or that they simple can’t smell the tasty vegetables due to the strong odors.  The positive thing about this group of repellant is that they are completely natural and once planted should only require inputs same as the other garden plants.
Among the many plants that are purported to repel deer are yarrow, lavender, marigolds, rosemary, oregano, sage and thyme.  The great thing about these plants is that most perform multiple tasks; repelling pest insects, inviting helpful insects, providing food or all three. 
If all else fails, there are a few “last resorts”.  The first is making a pepper spray concoction from hot peppers and spraying the solution over the garden plants.  The reason this is a last resort is that every rain requires a new dosing and it uses valuable peppers that could be best enjoyed as food instead of deer repellant.
Another last resort is the gun.  Of course, this is not easy or foolproof in a lot of cases.  For one, state laws (including hunting seasons, tags and permits) must be obeyed.  Not everyone is allowed by local law to shoot where they live.  Even then, it only takes care of the immediate problem and other deer are free to move in and continue the destruction. 

The state where I live (Kentucky) in 2008 revised statutes to allow deer control tags to be issued in cases where: 
  • Deer hunting occurred on the property during the previous deer season
  • Standard deterrent measures recommended by a department representative have proven ineffective or are impractical; and
  • A department representative certifies deer damage to crops, gardens, and property or wildlife habitat.
Again, please check local and state laws before discharging a firearm or hunting deer.
The final “last resort” is the fence.  Fencing is costly to build to a height that deer won’t attempt to jump and it can limit any garden expansions.  However, a fence to a height of 5 foot or so will at least deter them somewhat.  It is also an adjunct solution.  A fence of that height can make it easier to trap them for a moment to shoot them.  It also gives you a base from which to hang repellant.
Rabbits
Rabbits can wreak a lot of destruction on a garden as well.  Pound for pound they are probably more harmful than deer. 

Luckily rabbits can be stopped by most low cost fencing options.  In fact, in the early 1900s in Australia, three fences, one nearly spanning the entire continent from north to south, were erected to prevent rabbits from encroaching further.  Rabbits were an invasive species there.  I bring up this odd bit of trivia to point out the fact that the larger the fence, the more likely that erosion and other animals will breach it and allow rabbits inside.  This is exactly what happened in Australia.  The fence must be maintained.
Most rabbit fences are made of chicken wire, which is a thin strand galvanized steel woven wire fence material.  The shorter 36” height should be used and the first 6-8” should be buried in a pre-dug trench to prevent burrowing under or erosion from rendering the fence ineffective.  Stake should be driven in the ground at appropriate distances to keep the fence in place.  The wire can be stapled or tied to the stakes.  This fence will also help with raccoons.
In addition, lavender (also mentioned above as a deer repellant) is also a rabbit repellant.  With so many uses not just as a pest repellant, good insect attractant and more, it just makes sense to plant this one.  Rabbits also hate garlic; so again, you can keep rabbits (and vampires) away and enjoy the multiples uses of a delicious plant.  Foxgloves will also repel rabbits but with only one use (other than being aesthetically pleasing) I wouldn’t really bother with it unless it is a last resort before harming the animals.
For those who have no qualms about harming rabbits, a .22 LR or even a strong air rifle will do the trick.  Rabbits are delicious to boot.
Gophers and Moles
Although listed in the same category, these two mammals are different in the ways that they harm a garden but similar in how to deal with them. 
Moles are a lesser concern as they do not eat veggies but instead eat grubs, worms and other insects.  This in itself is not a concern but for the air pockets around roots that they leave which damage and kill plants.  Moles rarely emerge from their burrows.  Gophers will come out of their holes to eat your garden. 
Some methods of prevention will require identification.  This is not a difficult task.  The first obvious sign of a gopher is that your veggies are eaten (see above).  A mole will only leave wilted and/or dying plants.  Both animals create mounds.  The gopher creates a mound from which it pushes dirt and exits.  The mound will have a hole (which may be loosely plugged) and the dirt will be pushed in a crescent pattern.  The mole will push straight up and usually will not leave a hole.  The dirt will mound in a nearly perfect circle.
Unfortunately, there doesn’t seem to be a viable natural method of keeping pocket gophers and moles in check.  Poison can be used but I find this method wholly undesirable. 
The first method is to simply build a barrier.  This will require trenching down about two feet and burying your fence to that depth.  If properly planned, this barrier could serve as a rabbit fence and gopher/mole fence in one.  Just be sure that the wire weave on the fence is small enough to prevent the smaller ones from going straight through.  An alternative is to fill the trench with rock or cement.  The trench and rock could be used in conjunction with the fence.  If you are building raised beds, the fencing can be nailed to the bottom of the frame or laid in. 
The second viable method is trapping but this will require more maintenance than even the fence.  The traps will have to be emptied and reset and new tunnels will need to be addressed.  Victor makes what is perhaps the most popular set of traps for gophers and moles.  Just be aware that there are separate traps for each.  So identification of the culprit is going to be necessary (see above).
Birds
I’ve never had a major garden problem with birds.  Occasionally I will find a peck mark in a tomato or realize that they’ve dug up seeds I’ve just planted.  In most cases birds actually help a garden by eating harmful insects. 
However, I concede that there may be situation where they become a problem.  In these cases, you can use a frightening device such as the aluminum pie pan you would use for deer.  Owl and snake decoys only work for a short while.  That is, until the birds realize they are immobile.  You can also take countermeasure to eliminate nesting areas and perching areas.
Summary 
No pest control method is 100% effective.  Fences break, erode, blow down or are jumped.  Killing the pest only leaves a vacuum that is quickly filled by another.  Pests will build immunities or otherwise ignore companion plantings occasionally.
The best approach is a multi-pronged approach using a double fence broad-spectrum repellant.
The proper solution, of course, will vary with your particular pest problems, garden size and other factors impossible to list here.  You could add pie pans with soap rubbed on to this setup to repel birds and add an additional layer of deer defense.
The important thing to remember is to use multiple options that address more than one pest to maximize your money and time.  - Jason, Editor of The Self-Sufficient Way.

1 comment:

  1. "I've been using Havahart's deer off repellent since it targets the deer’s sense of smell and taste. Others only work on one sense. And they don’t work well.
    Here's the repellent I use:
    http://www.deeroff.com/advantage"

    ReplyDelete