Building a circular fence

Discussion in 'Planting, growing, nurturing Plants' started by sweetpea, Apr 7, 2005.

  1. sweetpea

    sweetpea Junior Member

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    Hi, all,

    I'm new to this board, and am looking for some help in designing a wire berry fence that will be in a 30 foot circle (95 feet circumference). What I am imagining are the forces on stretching wire around a curve, instead of a straight line, will slowly but sure pull the poles inward, and the traditional diagonal bracing won't help. Is it just a matter of putting the poles in so deep they won't pull inward, or am I missing something here? Trying to keep it as inexpensive as possible, not wood.

    Thanks very much!
     
  2. mossbackfarm

    mossbackfarm Junior Member

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    Hi sweetpea

    You're right.....the tension of the wires will pull the fence inward, regardless of how deep you sink them, and the only way to stop that is with brace posts. Depending on what's going on inside the circle, that may be diagonal posts braced inward supporting the circle, or H braces. But you don't want to use wood....

    There's a company that makes T post hardware that allows you to use them for braces....they are a little snarky to use, but they may set you up
    https://www.wedgeloc.com

    Cheers

    Rich
     
  3. AmandaM

    AmandaM Junior Member

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    Sweetpea,

    If the fence is simply to provide an upward support for growing the berries, then there is no need to actually strain it and therefore you could loosley attach chain mesh to a circle of star pickets and there won't be any inward force on the fence.

    If on the other hand you are trying to enclose (or exclude) strongish animals, then you will need to either;

    a. brace each picket with a diagonal strut from near the top of the post, at at least a 45 degree angle to the ground outside the circle, anchored with a tent peg or some such item. The problem with this solution is of course that you will have greatly incrased the space required to build the structure, and you will have a circle of wires outside the enclosure for people to trip over.

    b. Space-wise it is more economical to cross-brace with diagonal beams in a criss-cross pattern between the tops of the posts, but these would need to be 30 foot long and obviously expensive and unwieldy to install. Essentially this would become a gazebo, which would be very pretty anyway.

    Amanda
     
  4. sweetpea

    sweetpea Junior Member

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    Rich, Thanks for the site! Those look like great poles.

    Amanda, I think the loose wires will be the answer. I need to control the berries, but it's not the end of the world if the wires are not quite tight.

    Oddly enough, this is a permaculture design that has a great use of space and paths with the mandala pattern, but they don't recommend any type of fencing! Although I occasionally see them talking about chainlink, but that's way out of my budget!
     
  5. AmandaM

    AmandaM Junior Member

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    95 feet is around 30 metres, we purchased 30m rolls of chain-link dog fencing for about $100 at the rural suppliers a few months ago - and this was tall stuff, about 1.8m high. However, if you are just using it to train the berries, garden twine may do the job just as well at a fraction of the cost.
     
  6. derekh

    derekh Junior Member

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    I need to do some fencing in soil that is pretty tough and the idea of digging holes is not appealing.

    It's a pity those products from Wedge Loc do not suit the star pickets commonly available here. Are there any alternatives available in Australia other than the standard way the cocky's wire everything together using a Cobb & Co knot ?

    Wedge Loc could do well if they adapted their products to star pickets and found a distributor here.

    Just my 2c worth.

    derek
     
  7. darrenhatina

    darrenhatina Junior Member

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    This is actually quite an interesting physics problem. I'll quickly go through the physics of it then give you a fun exercise to demonstrate it.

    Fence posts and there foundations must support the forces to which they are subjected. The magnitude and direction of the overall force is the sum of the component forces. In this case the first component force is gravity which acts straight down and would be proportional to the total weight supported. The other is the force of tension of the two wires attached to the post. This force is also proportional to the weight supported. If the fence were straight these two forces be in equal and opposite directions so would balance each other out. In a curved fence the forces are at slightly different angles so you get a net force that acts towards the center of the circle. If you add these component forces together you get an overall force that acts down and towards the center. This is the force your post and foundation must resist. So how to best resist this force?

    Time to grab two friends... Now form a circle so that you are within arms reach. Next imagine that you are the post in question. Legs together support your own weight and find a balance. At this point you should be standing straight. Now pretend your arms are the wires, extend a hand to each of your friends and have them pretend to be vines ladden with yummy fruit pulling steadily with the same force on your wires aka arms. Again find a balance. Take note of your position. Now all of you hold hands, stand straight as a post and slowly lean back until all arms are fully extended and under tension like wires. The stronger your arms the further you'll be able to lean back.

    This should show you how to build your fence?

    Good luck!
    Darren
     
  8. sweetpea

    sweetpea Junior Member

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    Darren!! Yes!! This is what I was looking for! What a great visual aid! I knew there were different forces with a circle like that, and it all seems so simply now that you've explained it! Thanks very much!

    With this plan of 30 foot circles, I can fit 9 into 1/4 acre, which allows for 900 feet of berries, 45 fruit trees, 9 nitrogen fixing trees and the rest vegetables, which is a bit daunting laborwise, but the perimeter deer fence will be much smaller than spreading these out in the traditional way, and hopefully everything will contribute to everything else, saving me time and effort.
     
  9. SueinWA

    SueinWA Junior Member

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    If you will be fencing deer out of your growing area, may I make a suggestion?

    Forget the 7 ft-8 ft fence that most people use for their perimeter. Forget the double fence. Get 3 ft wide welded wire fencing (I use the 2x4 inch mesh). Lay it down on the ground around your perimeter.

    That's it. I'm sure you're familiar with cattle guards, grooves in pavement that threaten cattle with getting their feet caught if they step on it. It works so well that they've found that PAINTED stripes on the pavement have the same effect. This same fear of getting their feet trapped is why this method of fencing keeps deer out. And they won't jump it because they don't know how far it extends.

    I used to rent a property where I could have a garden, but not fence it. I used this method against the 6 deer that passed by my garden twice daily going to water. I watched them stare longingly at my lettuce, peas and corn, but the only part I lost was part of a pea vine that escaped its trellis and reached beyond the fencing.

    Yes, I know it sounds too simple. But it works.

    Sue
     
  10. sweetpea

    sweetpea Junior Member

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    Sue, that's amazing! And that is my other project, 800 feet of 7 1/2 foot fencing....gulp....and I know what you mean about the cattle guards. But if it's only 3 feet, they don't jump it? How long did you have it down?

    I've noticed that whatever I've used to stall them out, they fiddle with it until they learn how to get around it, in maybe 6 months they've nosed aside bird netting and yanked at branches on fruit trees right through the netting.

    Do raccoons and rabbits get deterred by this? I do hope to slow them down as well, since the raccoons climb the fruit trees and the branches break under their weight on the newer trees.

    And while we're at it, got any cures for gophers? :lol:

    I've tried juicy fruit gum, traps, wind noisemakers, hawk poles...nothing works!
     
  11. SueinWA

    SueinWA Junior Member

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    The deer don't seem to want to jump the flat fence, even if the food they want is right on the far side of it and the wire is only 3 ft wide. That did worry me in the beginning, but I am wondering if it's because of the placement of their eyes. As prey animals, they can look all around in a glance, but like horses, they may not be able to see their feet. They step on the edge of the wire, sense a trap, and don't know how far it extends. If you saw a chasm in front of you, you wouldn't try to jump it in two bounds, because the "trap" is where you land on your first bound.

    My fencing was right at the edge of several small beds (4x4 ft), so the food was right there for them to look at. I was only there a year, but they never got it.

    My friend had gophers and moles, and didn't want to use poisons, so she took all the litter box deposits from her 3 cats and pushed them down the holes. The gophers moved out, but the moles hung around. Moles don't reuse their tunnels, but gophers do. And gophers are the ones that damage plants. Moles are only looking for earthworms and other bugs. Their tunnels help take rainwater underground. Native Americans would never kill a mole, but if they found a dead one, they would make their medicine bag of it's skin.

    For rabbits and raccoons, I would just use a short electric fence, the netting kind. They usually don't have them in farm stores, but they can order them for you. They're also good to keep predators away from your chicken house.

    Sue
     
  12. sweetpea

    sweetpea Junior Member

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    Thanks, Sue. I've also heard about the cat litter, that might be worth a try. And that's great about the deer guard, thanks again!
     

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