3 types of nematodes, they attack different plants. tagetes is the marigold for repelling other bugs, but draws spiders. Sand here, compost eating sand in a drouth or drown climate, but compost helps deter nematodes - deep piled high rich compost - nothing is an instant cure in gardening, you have to go for the long plan.
By the way, nematodes can spread by soil, water, and wind, so it is a constant battle. I have raised beds, and yes, I still fight nematodes...
