One of the best companion plants in the garden — French marigolds (Tagetes patula) excrete thiophene compounds from roots that deter nematodes; plant thickly for 3+ months for best effect. Strong scent deters many insects. Plant near tomatoes, peppers, cucumbers, and squash. Deadhead spent flowers to prolong blooming. Very easy from seed — direct sow after last frost or start indoors 6–8 weeks early.

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