A garden fence also offers privacy or can be used to support vine vegetables such as cucumbers or beans, but it's also is an effective way to keep deer and pests out of your garden. Deer can jump up to 8 feet high, making shorter fences useless. Extending fences upwards allows you to keep the deer out without the need for new construction, which may be expensive or complicated to do yourself.
Measure the height of your fence posts and subtract their height from 8 feet to find the height you need to add if you want to keep deer out. Otherwise, decide on the desired height for privacy or plant supports. Purchase a pole for each post that is 1 foot longer than the needed height addition.
Set the new poles against the existing posts, overlapping the bottom 1 foot of the new pole over the top of the old post. Lash the poles to the posts tightly with heavy twine or wire.
Cut a length of plastic or wire-mesh fencing to the length of your fence. Use bamboo fencing, which comes as a panel or on rolls, if adding height for privacy. Attach one end of the mesh or bamboo to the first pole with twine, making sure the bottom of the mesh overlaps the existing fence by at least 6 inches.
Stretch the mesh or bamboo to the next pole and tie it in place. Continue stretching the mesh to each of the posts until the fence is complete.
Tie white strips of cloth near the centre of the fence if creating a deer fence, spacing each cloth 1 to 2 feet apart. This allows the deer to see the new fence at night so they don't attempt to jump over it and knock it down.
Set the fence extension at a 45-degree angle to make it even more difficult for the deer to jump. Stretch wires between the post extensions instead of using mesh if your deer problem is not extreme.
Lash the poles to the existing posts tightly, or the weight from the mesh may pull the extension down. If trellising heavy plants, such as melons, screw the post extensions to the existing posts so they can support the weight.