I pose this out of complete ignorance. I am not sure I would recognize a nematoid (aka "roundworm"-surely not?) if it jumped up and said "boo".
From a thread below, I formed the impression that nematoids are garden pests to be avoided.
But a garden show that I listen to online from BBC Radio 4 (UK), had a panel that raved about the beneficial impact of nematoids and 'nematoid products'(?).
Is it the ocean that makes the difference? I am a resolutely organic veggies/fruit gardener here on the North Eastern seaboard-should I be attracting or repelling nematoids? I do see the occasional coiled-worm, shiney, small (penny-sized) bug in my raised- garden beds-is that what I want/don't want?