My grandmother planted marigolds around every tomato, and I’ve always wondered if it actually does anything. She swore by it, and her tomatoes were the best on the street. But she also composted religiously, so who knows what made the difference.

While planning my beds this spring, I checked the pairings on the companion plant finder at Gardenvoila, and marigolds, basil, and chives all came up as commonly suggested neighbors for tomatoes. It also warned against planting them near brassicas and corn, which I hadn’t considered.

I’m trying it with a few plants and leaving one tomato unprotected as a rough comparison. Has anyone run a similar side-by-side? I’d like to know whether the benefit was pest reduction, pollinators, or just a prettier bed.