Solanaceae — Nightshade family

Shared risks

• late blight (Phytophthora infestans)
• early blight
• Verticillium and Fusarium wilts
• Colorado potato beetle
• tomato/potato hornworm

Named risks, not an arbitrary score: these are the organisms that carry over in soil, debris or volunteers.

Rotation guidance

Leave 3 years before returning any nightshade family member to the same bed. Rotation concerns previous seasons in a bed; it is separate from which plants grow together now.

• Tomato and potato share late blight; keep them apart in the same season and rotate between seasons.
• Peppers and eggplant are hosts for the same wilts and flea beetles.

Sources

• Managing plant diseases in the home garden (2023)
• Home, garden, turf and landscape pests (2025)
• Living soil, healthy garden: crop rotation and soil health (2023)

Exceptions and small-garden notes

Short crops (radish, arugula, baby leaves) still count as occupancy for the family. In a garden with one or two beds, strict rotation is impossible; instead, alternate families within a bed by half, remove crop debris, choose resistant cultivars and keep a bed history so the planner can warn you.

Other families: Brassicaceae · Fabaceae · Cucurbitaceae · Apiaceae · Asteraceae · Amaryllidaceae · Lamiaceae · Amaranthaceae · Poaceae · Rosaceae · Other families