Can you tell me how you trapped them?

I used plain old mouse traps with peanut butter.

I placed chicken wire at the bottom of my raised beds, and for several years I had no problem. Eventually, I did get several infestations. That may have been due to the chicken wire rotting away, or to the fact that eventually the soil in the beds (rising every year because of mulch) gave them enough depth between chicken wire and the surface.

When that happens, I do two things. First, on finding a tunnel, I run the hose in there for an hour or so. This waters the bed, collapses the tunnel, and I hope at least kills the young ones. The second thing I do is to punch a hole in the tunnel, pour rat poison, and close. You can go through a box in a month on a bad year.

What I should have done is, when you make the bed, get hold of, say, 200 lb of broken glass. There used to be a recycling center near my place with a huge pile of ground glass. Put it at the bottom of the bed. Fill the bed. The voles do not like to dig into the stuff and they stay away. This solution lasts forever.

As far as buying the compost, yes, it is expensive. My beds are compost and I never bought any. The trick is in putting free organic matter in the bed to compost. The soil will not be good right away, but there are numerous vegetables that will grow in it while the compost becomes good soil, including potatoes, squash, melon, and tomatoes.

Free organic matter available in ten tons quantities or more includes (at my place) manure, leaves, and wood chips. Wood chips and manure can even be delivered to your front door free.

Advice needed:

How big should the holes in the wire mesh be to keep the voles out?

How deep should the glass be and what size should pieces of glass be?

What vegetables do they eat? I've heard they like root vegetables best - such as carrots and potatoes. Are there others?

Do you think they'll climb up the wooden sides of a raised bed?

In someone's blog, they said that possums eat the vole's nestlings. Is that true? Should I keep the possum?

Thanks for the broken glass suggestion. I was also wondering about pea gravel or something else like that? DH is a builder and has construction trash or left overs all the time.

The holes should be at least 1/4" wide for the wire mesh. I'm not exactly sure which vegtables they like the best b/c I just have a bad time with them on just about everything. I will have to admit that they did not eat my tomatoes for the past few years.

I also have opossums, groundhogs, racoons, foxes and hawks in my backyard. They have done NOTHING to the voles.

Yes, they do climb the walls easily, but in my experience they much prefer to tunnel in from under the beds. They like every vegetable. I can not give advice on the ground glass method because I never tried it directly, but it does make sense to me. Only problem is density. You really want a shard every inch. Gravel will do nothing to them, it has to be a sharp thing that cuts their paws while they dig.

As far as predators go, only snakes and cats are really effective. And coyotes. Foxes are somewhat effective, but only if there are no rabbits in the area.