Symphylans

Scutigerella spp

Symphylans resemble small (to ½”) translucent centipedes and live in the topsoil, where they mostly consume decaying organic matter. However they will also feed on plant roots and seeds and this can be a problem when they are present in large numbers. Older plants can usually tolerate some damage, but smaller plants and seedlings may be stunted or killed.

Ironically Symphylans prefer well structured soil with lots of organic matter (they can move around more easily) which is exactly what you are trying to create. They are quite mobile in the soil and difficult to control. The best thing you can do is encourage natural predators.

Image: David Gent, USDA Agricultural Research Service, Bugwood.org