bestgardening.com - Everything for New Zealand Gardeners
Design Plants How-To GardenHub
Kowhai - 'Sophora microphylla' Click Here for Article
   Events  |  Garden Open  |  Societies  |  Kids Pages  |  Books  |  Photo Gallery  |  Garden Life  |  Nature's Garden
Home Garden Tasks Garden Events Event Reviews

Gardens Open Newsletter Subscription a-z Index Classifieds Garden Societies Site Map About Us Search




.

The Rabbit/Possum/
Hare-Proof Fence


By Gio Angelo - Builder and Author, Ruth Chapman - Gardener and Assistant Designer, Sue Chapman - Farmer and Provider, and Bella - The Cat

"Necessity is the mother of invention". Ruth´s vegetable garden was being ruined by rabbits, hares and possums. Young carrots were being pulled out, brassicas were eaten down to nearly the roots and attempts to establish burrows were made regularly. The cat wasn´t helping either – she caught the odd rabbit but used the soft garden soil for her toilet area.

So the war was on. We trapped, poisoned and shot the pests (except the cat) at every opportunity but we hardly made a dent in their populations. They were winning so some other strategy had to be found. It was really Ruth who came up with the idea when she was telling me of the cage her grandfather had built to keep the birds off his garden. So why can´t we install a cage to keep out four-legged pests?






Garden Cage project Garden Cage frame

Garden Cage completed Garden Cage - completed!
After some phoning to local companies that produced tunnel houses, and raking through the internet for national suppliers I soon realized that it was going to cost more than our budget would allow. The most suitable product I found was produced by an Invercargill company but it was going to cost over $2000 to cover our 5 metre square veggie garden – and then it would have to be in a configuration of two tunnels.
An experimental hoop was built to see how long it would stay up. A metre length of 18mm reinforcing rod was driven into the ground on each side of the garden with 500mm above ground. The ends of a piece of 18mm alkathene were then slid over the reinforcing rods to complete the hoop but it flung about like a live eel. By putting two wooden poles in the middle it settled down to quite a solid structure. The poles worked well as the raised garden was in two strips about 500mm apart and by putting the wooden poles, one on each side of the path, the gap between them at the top was just right to hold the alkathene steady.

The trial hoop proved to be a success and stood alone for over a month during which we had two very strong wind events (one blew some spouting off the roof) but the structure did not suffer. The only problem was the height of the hoop at the edges. Ruth said she wanted the height increased so she could work comfortably, without stooping, in all parts of the garden. This simply meant increasing the length of the rods above the ground and thus being able to raise the height of the Alkathene. The increased height didn’t compromise the stability so I went searching for materials and committed to some spending (so far the bits and pieces had been scavenged from discarded material from the family farm next door).

I also decided to increase the diameter of the reinforcing rod to 20mm to give a firmer fit for the alkathene. The internal measurements of 20mm alkathene can vary from 18.5mm to 20mm depending on what type of pipe. I found that the 20mm high-density type was perfect because of its tight fit on the 20mm rods and its rigidity but with enough flexibility to bend into a hoop and also help take some force of the wind.

Trial Hoop
Trial Hoop


So my material list for 5 hoops to cover 5m was:
  • 5 pieces of 8000mm x 20mm high density alkathene and about 4 extra pieces 5000mm long to use as braces between the hoops. This was kindly supplied from the farm’s discarded water system. (I could see the puzzled look on Sue’s face as I dragged it down the road. “Another one of Gio’s mad schemes,”; I could see her mouth.) No cost.
  • 10 pieces of 1500mm x 20mm reinforcing rod. The firm in Dunedin I bought them from was very obliging (another puzzled look when I told him what I was making) by helping me find the right type and size and cutting the 6000mm lengths they supplied down to the size I wanted. I pointed the ends of these with an angle grinder to make them easier to drive into the ground. Cost: $120.
  • 14 lengths of wood 2500 x 50 x 50mm. I should have used treated timber but I had some framing over from my last mad scheme. I also used some other pieces to make a simple gate. Approximate cost: $40.
  • 12metre by 12 metre piece of plastic bird netting. I found an outlet that sells bundles of netting discarded by vineyards and fruit farms – perfect for my use. Cost: $75.
  • Some screws to screw the alkathene to the wood, and a roll of duct tape to cover the head of the screws so that the netting wouldn’t catch on them. The tape helped to strengthen the joints too. Duct tape is a very strong and durable material. Approximate cost: $20.?
  • Total cost to me $255 and I am sure with a little more scavenging this could be less but if the alkathene has to be purchased then it would cost $120 more.

Now all I had to do was to assemble it. Easy. .
  • Drive the rods 500mm into the ground, centres 1200mm apart.
  • Slip the alkathene halfway down the exposed rods.
  • Attach the poles to the top with screws and tape.
  • I cut up some old waratahs into about 300mm lengths, drove them into the ground at the base of each pole and attached them to the poles to give even more strength.
  • Screw the extra lengths of alkathene between the hoops (cover the screw heads with tape) to give it more rigidity.
  • Then put in some wooden bracing wherever you think it is needed. I found there wasn’t much needed.


Cage leg
Cage leg
At this point I constructed a simple gate with some scrap wood, braced it with some treated ply wood and hinged it to one of the end poles. The last job was to fit the netting over the hoops, do some cutting and fitting around the gate and anchor the ends down. I used the existing brick mowing strip to anchor the netting and to keep the right tension on it.

I don´t like gardening but this was fun to design and build. No more pests in the veggie garden, Ruth is a happier gardener and the cat has found another spot for her toilet.
Cage base
Cage base
    List your garden event or society
List your event
It's free! Email the Editor at bestgardening.com now


* Back to Top * Home * Garden Hub * How-To * Plants * Garden Design * Gardens Open *
Copyright 2001 bestgardening.com Limited. All rights reserved.
webmaster@bestgardening.com
Last revised 23 Mar '12