The Problem Index → Garden
Root-knot nematodes have taken over my beds
The famous companion-planting advice is mostly wrong, but the one specific version of it is genuinely right — and the difference is whether you give up the whole bed for a season.
What actually works
◇ Plausible
French marigolds for root-knot nematodes
A solid bed of French marigold for an entire summer, in moist soil, suppresses root-knot nematodes via alpha-terthienyl. A few scattered among the tomatoes does nothing.
A packet of seed◆ Proven
Rotation and resistant varieties
Look for 'VFN' on tomato seed — the N is nematode resistance. Combine with rotation; nematodes return once susceptible plants go back in.
◇ Plausible
Solarization
Clear plastic over moist soil through the hottest weeks. Real in hot climates, weak where summers are mild.
Also searched as
knots on tomato roots · root knot nematode · galls on roots · stunted plants knobby roots · marigolds for nematodes · soil pests roots