I have a problem with crickets eating my seedlings and young plants. I have found very little information on keeping crickets away, as this doesn't seem to be a problem for most people. Without resorting to synthetic chemical pesticides, how can I keep crickets from eating my young plants?
This article talks about prevention:
Mow tall grass and weed flower beds. Crickets love tall grasses. If you have tall grasses near or around your house, it's best to keep them trimmed low. Crickets also live in debris. They are attracted to moist, shaded debris, like grass clippings.
Prevention is important because if you kill them (through whatever method mentioned below), they'll just come back unless you destroy their habitat.
Entomopathogenic nematodes are one method of control. Shop for "nematodes" and read the label to verify that crickets are targeted by the particular type of nematode in the container. If you have mole crickets, Steinernema scapterisci will kill them. (See this article for sources.)
Pyrethroid is a natural (though still toxic; and often only available commercially as a synthetic) poison that may be effective against crickets. Check the label.
If you shop around, you'll find cricket bait available that is listed as suitable for organic production. I presume these are "safer" pesticides. Note that, at least on the websites I found, they are not available in several states.
Some of what you find on the internet says that "natural predators" will control crickets: birds, toads, etc; you should encourage these predators into your garden. The U Florida extension service article linked above says this isn't effective.