Building fence can be a challenge in rocky, frozen or swampy ground when it’s impossible to dig post holes efficiently, or set posts with a tractor-mounted post-pounder.Michael Thomas, Salmon, Idaho, custom fence-builder, said options in rocks include digging holes with a backhoe, chipping away at the rock (if it’s a formation that will chip and break), prying them out with a hand bar, or using a rotohammer electric drill that runs off a portable generator.
“This works for drilling small diameter holes into solid rock to insert a steel post, or even a bigger hole for a brace post,” said Thomas.
In some terrain, where it’s not too steep and there are surface rocks, you can create an above-ground basket/cage of rocks as a brace to anchor the fence.Gather/stack the rocks and secure them with net wire, or make a cage and put rocks into it.
“A cage 3 to 4 feet in diameter makes a solid anchor to secure your fence wire and stretch it from there,” he said.If terrain is too rocky to set wood posts, you can usually put steel posts into the ground deep enough to hold, using rock baskets every so often for braces.
Another strategy for rocks or frozen ground when using a post pounder is to use a metal “post” to create a pilot hole.The metal post will often go down through rocky ground if it’s not solid bedrock, pushing aside the rocks, or penetrating frozen ground, whereas a wood post would be forced out of line or shatter.One of Thomas’ neighbors made a 7-foot-tall metal pilot post to create holes for wood posts in difficult conditions.
“The pilot post is only 3 or 4 inches in diameter and creates a hole to put the wood post into.The pointed bottom is solid steel about three feet long, and the rest is hollow, like well casing. This makes it a little lighter to carry.The top has a solid cap for the post pounder to hit.You drive the pilot post as far as you can, pull it out with the tractor loader, and insert your wood post into the pilot hole and drive it in—forcing it into the slightly smaller hole—and it is very solid and secure,” explained Thomas.
Other alternatives are an above-ground fence such as a jackfence (buck fence or buck and rail fence) or worm fence.A worm fence is created by stacking logs or large diameter poles upon one another, interlocking in two directions.The finished fence is a continual series of corners/angles.This type of fence is safer for cattle than horses, since a horse may be injured if it gets crowded or chased into a corner by a herdmate.
A pole jack fence works where ground is too rocky or swampy to set posts, but in windy country must be anchored so it won’t blow over.A strong gust of wind can sometimes tip over a whole section of fence.
“To keep it from tipping over you can hang a large rock under some of the jacks or make a small rock basket (net-wire cage) with the jack secured to the cage,” he said.