Voles do. I lost half my cuke seedlings last week that way. They also like to eat the tops of kale and other brassicas, and often leave visible paths in the grass or mulch.

If you suspect voles, put out a few traps baited with peanut butter or almond butter. If you catch any, then there are more and you'll have to find a way to exclude them from the salad bar.

I haven't seen any voles, but I do have a LOT of brown and white mice. There's no way to get rid of them all even if I wanted to.

I'll try starting some more indoors and then transplant when they get big enough, maybe by then the little nibbling won't be so bad.

We still think the slugs are doing it.
The butternut sqash and green bean leaves are under attack now. Inly the tiny shoots and leaves that are touching the ground are eaten. Also, after looking more closely, the leaves are being eaten from the to surface, not from the edges like a vole or mouse would eat. No catapillars or other worms have been spotted yet, but every damp day, tons of slugs are all over the garden area.

I would say slugs. Some beer traps are in order here.

I'm sure its slugs. They will kill a small seedling, easily.

Read my post linked below. Do nitely patrols until the plants are big enuff to fend for themselves.

Here is a link that might be useful: Gardeners Best Kept Secret

OK, Thanks for the information. I honestly never thought slugs would eat plants, but it's the only thing I have seen in the garden. After one stormy sunday a couple weeks ago, there must have been over 100 slugs on the wooden posts in the garden.

I'll give the ammonia and beer traps a try.

Thanks again!

When I see slugs, I give 'em a little salt bath. Just sprinkle liberally on the slug...be careful with the salt around seedlings.......I actually pluck all of 'em up and salt them in a pile. I do the eggshell thing too...seems to work.

I recently read that earwigs often eat seedlings and small plants but go largely unsuspected. Putting out beer or oil is also said to attract and drown them.

I've used egg shells for snails/slugs. This year we are trying a strip of copper around our planting box.

I lost the first two plantings of vine crops to slug damage. One night, I went out with a flashlight to find 11 tiny slugs on one two inch leaf. Even though I handpicked and squashed them, the plant did not survive the attack.
The first planting of cucumbers did not germinate, so I resowed. When they all germinated, I decided to transplant half of them to another section of the garden. Last night, I was out there 3 times picking and squishing..This morning most of them look desperate. It's only the one section of garden space that gets the most shade that is the problem. Crop rotation and less leaf mold next season hopefully will solve my problem.
Egghead, I hope your second sowing is more successful than the first.