You have some powerful teethed rodents. The answer will depend on where you live and your winters as voles will tunnel down below the frost line to keep warm in the winter. Some area's could be inches or several feet.

A very effective in ground barrier for voles, groundhogs, gophers, etc. is simply an outward facing L placed 1 foot deep and 1 foot out. The burrower that meets that simply gives up rather than trying to find just where that barrier goes.

Yes, maifleur (I love that name), they have strong teeth ... and excellent gnawing skills. I was amazed to see that they'd bitten gashes through galvanized steel. Now for Plan B ... the new fencing material will be arriving in a couple of weeks. I expect they won't get very far sharpening their incisors on it.

kimmsr, that's a great idea. I think I will alter the plan to 1 foot deep and 1 foot out (leaving 2 feet above ground). That will be easier for me and harder for them, I expect.

I guess I'll still have to stomp the snow down after a heavy storm to keep them from crossing the barrier during the winter ....

Even if you don't manage to keep them out you have done the painful part of getting fit. So stay with it and hopefully the voles will move on.

A question I have always wanted to ask when someone mentions digging out rocks. What are you plans for them. If you build a fence maybe chipmunks will come or a snake to eat your voles.

In this case I put most of them back in the trench, to hold down the fence (especially at the seams). The ones I dug out of the beds were used to build small stone walls around the beds, or hauled off to the woods.

There are plenty of snakes around here, though none of the vole-eating variety.

nygardener, I'm thinking of implementing the same solution to my garden. Would you post a follow-up, and let us know if the solution was successful? Thanks!

Yes, it worked great. There were a few voles left inside the fence after we completed it. I trapped those out, and haven't seen one inside since (knock wood). It's made a huge difference; it was impossible to garden without it. I think it helped to mow the surrounding field at around the same time.

Since there are deer here too, I mounted a 4-foot-tall wire fence above the vole mesh, for a total of 6 feet.

If you use stainless steel, although it's expensive, it will never corrode, and it won't leach zinc (the coating of galvanized steel) into the soil. You can get either welded or woven wire, in various thicknesses. Here's the one I used. (In bulk, it's much cheaper than the prices shown.) I had it delivered in 4' x 20' sections so that they would be easier to handle and lift, and overlapped them about a foot. You can order samples to get a feeling for the material.

Other hints: A rented trench digger is a big help in getting the trench started. Also, if there's a metalworking shop near you that will receive the delivery, bend the panels lengthwise 1 foot from the edge, and deliver them, you'll get cleaner results and save a lot of work. (They might prefer to cut the material themselves, and may have other ideas or be willing to help with the installation.) Order some extra material for the bottoms of the corners, and have that cut and bent to overlap.

nygardner, Thanks for your very helpful response to my post under "m8kmida" user. I had trouble logging back into that account, possibly because I had a previous account (lukn2lrn) that I had forgotten about. Anyway, I wanted to be sure that you know how much I appreciated your quick response to my query, and all of the excellent suggestions on how to go about it. I'm putting in a new garden this year for my perennial plantings, and I think that it would be a worthwhile investment.