Would you consider using landscape poles (the 8 foot poles with 2 flat sides) as fence posts?
They are cheap and - I believe - pressure treated so they would not rot.
Would they be okay to use as an inner fence? This would be a fence around some Aspen trees to protect them from the horses.
No. I did it and the posts didn’t last in the ground much longer than untreated posts would have. They’re treated but not with as much stuff as posts made for ground contact.
I used them and they have worked out great. Mine are 11yrs old and don’t show any signs of rot.
There are two diff. kinds though so be careful. You DON"T want the ones that are labeled as “treated to resistance” these are basically surface treated and are not like true pressure treated lumber or posts/poles.
Most of the cheap ones are not made to go into the ground and have pressure treatment only on the outside. You want something pressure treated all the way through for fence posts.
We tried the cheap ones and they were a disaster. Termites have a tunnel of untreated wood straight up through the center. 
Bad idea. They rot around here in 5 years tops. Get good salt treated posts or 4x4’s and they will last 40 years.
We used some, and a neighbor did also.
Rot wasn’t so much of a problem (we don’t expect ANY wood post to last even a long time, much less forever), but the not putting them deep enough in the ground kinda was (but you run out of gumption real fast when you are working with a clamshell manual posthole digger in heavy clay interspersed with rock…)
However, the biggest problem was horses chewing on them. As with any softwood, once a horse gets to gnawing on it, they can be halfway through it before you even notice they’re chewing on it.
The timbers had two big things going for them – a nice flat side to nail the fence onto, and being a lot better than the resest of the crap being passed off for fence posts around here. The eight foot length would have been a plus also IF we’d had the equipment to sink them deep enough.
Locally, tamarack and cedar are reputed to be the best fence posts. However, I’m not sure any wood post lasts long enough to be worth the initial cost and the bother of upkeep. We had another neighbor who fenced their entire horse set-up with oak 4x4 with the bottom three feet soaked in some kind of preservative, thinking they were only going to have to build this fence once. Five years later, not one single post was still solid --they’d all rotted off at ground level.
greys…we pulled up some Pressure Treated 4x6’s put in 15 years ago for fencing when we were redoing fences a few years ago and they looked almost new. The landscaping timbers were mostly rotted through in half that time. Big difference here on our farm in very moist soil. Our farm pretty much sits on land that was part of the Great Dismal Swamp at one time. Groundwater is always close here.
Cedar that is shade grown (lots of sap in the wood in a slow growing tree) can last a very long time also and many cedar posts have been in use a very long time on some farms. I suspect PT wood would be a lot easier to get in many places. .
We used some on a windbreak and the termites ate them up to one foot off the ground.
Sure looked silly with the corrugated metal on the 2x4, the railroad ties still holding them and those posts inbetween eaten at the bottom, up in the air.:lol:
What if I live somewhere dry with no termites…?
See my post #3. I’m in Wisconsin.
As others have said, the cheap ones are only treated on the outside. They rot pretty quickly, regardless of your soil. We didn’t know that and used some to put up a privacy fence. It lasted 3 years or so and then a wind flattened the whole thing :sadsmile: We replaced the landscape poles with treated 4x4s.
If memory serves
I belive the landscape timber is a by-product of plywood manufacture. It is the core of the log from which the plywood veneer has been cut. There are two inherent problems. First this is the center or heart of the log which often has so much pitch in it that it cannot take up the PT chemicals. Second since the veneer has been cut with a huge knife in a lathe sort of setup there is no regard for the grain in the resulting post. the post is very straight but may not be very strong.
Dick
Thank you for a very timely thread!
I have landscape timbers that went in about 4 1/2 years ago, and last year I was already replacing broken posts. This winter I already have spotted three more that have broken. The pallet of remaining timbers is getting low so I have been wondering whether to get the same again 
or what would be better. The ground here is gravel (w/ lots of boulders - putting that fenceline in originally was a reeeeaaaalll stinker!) but we do get a fair amount of rain/snow.
I have used them in 2 diffrent locations/state 2 diffrent soil types.
While they may not hold up for the main fence that would get alot of pressure not only from horses but fence itself. For what you want they will work.
Cchewing if the chew it doesn’t matter if its granite they will chew it.
I have some who eat oak fence boards and other who won’t eat anything on the fence line ever.
I have used them as cavalletti ground poles and some are 12 years old, stay on the ground and are sound while my round rails rotted.
Guess Im lucky here in Vermont. Made a cedar post fence in 1980 which is still as strong as the day it was made. We cut spruce and poplar posts right here in the woods and use them to. Most of our dairy cow fence was spruce posts. Had to replace a few once in a while but not so much that it wasn’t worth the savings.
We used landscape timbers as fence posts for our Electrobraid fence (we did use regular fence posts for corners, gates, etc.) They were put in almost 5 years ago and have held up well.
This is the best picture I have that shows the posts:
I have used them around a riding ring with 2 boards on top - it worked ok I think because of the drainage and we dipped the bottoms before we put them in. If one did break, it wasn’t that hard to replace.
Would not use them for pasture though - not strong enough to hold up a regulare fence and have seen too many break if a horse leans on them - termite damage or not.
We used pressure treated 4x4’s - easy to put fence on and have lasted many years - just re-did (made it larger) a section - pulled up the old posts, repainted them and have used them as braces and for other fencing projects.
Nope
Previous owners of my place did it. They don’t hold up to the weather as well or horses bumping into them. I’m having to replace them one at a time.
Thanks for all theb advice. The reason it even crossed my mind is that the jump poles I have that are made of landscaping poles seem to hold up extremly well to the elements.
Ours are on year 4 and show no signs of rot or weakness. We put them 3 ft. deep with concrete in the holes. We have high water level and clay soil so it is wet soil a lot. No problems here.
We have electrobraid though and so the horses stay away from the fence. And I don’t have any problems with horses chewing wood, thankfully. Neither in the barn or in turnout.
