Companion planting basics for raised beds

Companion planting pairs crops that benefit each other through pest deterrence, pollinator attraction, nutrient sharing, or physical support. Key beginner-friendly combinations for raised beds: Tomatoes + basil (basil repels aphids, hornworms, and may improve tomato flavor). Beans + eggplant (beans fix nitrogen that feeds heavy-feeding eggplant). Cucumbers + dill (dill attracts predatory wasps that eat cucumber beetles). Carrots + onions (onion scent masks carrots from carrot fly). Corn + beans + squash (the Three Sisters: corn provides a trellis for beans, beans fix nitrogen, squash shades soil and deters raccoons). Marigolds everywhere (suppress root-knot nematodes, repel whiteflies, attract pollinators). Nasturtiums near brassicas (trap crop for aphids and caterpillars). Equally important are plants to keep apart: tomatoes and potatoes (same diseases), onion family and beans/peas (alliums stunt legume growth), fennel and most vegetables (fennel inhibits growth of nearby plants). Do not overcrowd companion plants; they still need proper spacing for air circulation and root development. Start with 2-3 proven combinations and expand as you learn your garden's specific dynamics.