If somebody has been chewing on your beans it may be a little bunny or woodchuck.
The solution for both of them is probably the same. You could use repellent spray such as hot pepper wax and deer and rabbit chaser with putrescent eggs in them. These sprays give the bean plants an off-taste. But once they find your beans, they're going to eat them anyway.
So you're going to have to use a different method to keep the critters away. I like to use bird netting. Just drape the netting over the bean plants. Secure it on either side of the row with some boards and that will keep those wascally wabbits away.
For bigger problems, if you have these animals eating a lot of vegetables and flowers through your whole garden you can just take some chicken wire and you can make a chicken wire fence. The key is to make a 90 degree angle at the bottom of the fence, bury this portion under the ground and have that angle facing away from the garden. When they come up to the fence and they start digging down they hit the buried fence so they don't get underneath it.
If you find the woodchuck hole, you can soak a tennis ball in ammonia, shove it down the hole, and then bury it. They hate the smell of ammonia. The woodchuck will try to push the ball out, but what happens? It rolls back down again. And then they get so frustrated they go somewhere else, but it doesn't hurt the animal.
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