I have be told they cannot survive in freezing soil. If you are thinking about grub control I think milky spore is a better choice. But do follow the directions - moist soil, apply and water in, otherwise you are wasting your money. Best And Happy Yardening, Nancy.
Will Nematodes Survive Cold Winter
Question From: R. Beck - ILLINOIS
Q: will nematodes winter out or will they die if soil gets to cold