Vole Barriers

I had planned to line our new veggie beds with hardware cloth in order to deter voles.  However, the hardware cloth is very, very expensive.  So I've decided to test the barrier methods mentioned on this website...trenching and weed barrier.  Keep your fingers crossed.

Using Barriers
In some gardens, especially vegetable gardens, it is possible to make a trench around the garden, about a foot deep. This is more easily done right after the garden is tilled. Most voles, tunneling right beneath the surface, tend to turn back when they hit the trench and they are reluctant to cross on top of the ground. It helps to make a trench down to harder ground, if possible. Vigilance is necessary and gardeners should be on the lookout for new holes on the garden side of the trench. Rob has grown potatoes and parsnips in vole infested areas using this method. Mulch or straw should be avoided in vole problem areas.
In some cases, such as a bog garden or flower bed, it may be more effective to remove the soil and line the bog or bed with galvanized steel mesh (hardware cloth), a layer of rock, or heavy-duty weed barrier. Any barrier needs to be without underground openings and extend to the surface. (See our Bog Making web page for more details.) While voles can chew through weed cloth, they usually don't, especially if one patrols the perimeter and collapses any approaching tunnels. We havebog gardens protected in this fashion. Doubling or tripling a weed cloth layer helps. Again, avoid mulches and look for new entry tunnels. Snow can be a problem, since voles will travel quickly on top of the ground, under cover of snow.http://www.pitcherplant.com/diseas/voles.html