{"slug":"tomato","commonName":"Tomato","scientificName":"Solanum lycopersicum","companions":[{"crop":"tomato","companion":"basil","type":"beneficial","mechanism":"shade_provider","description":"Tomato canopy provides afternoon shade that protects basil from leaf scorch and bolting in hot summer climates; useful pairing in mediterranean and arid beds.","strength":"moderate","source":"UC ANR Master Gardener publications"},{"crop":"tomato","companion":"carrot","type":"beneficial","mechanism":"shade_provider","description":"Tomato canopy shades carrot tops during late summer heat, slowing bolting and reducing greening on exposed shoulders of carrot roots.","strength":"moderate","source":"Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"asparagus","type":"beneficial","mechanism":"pest_repellent","description":"Tomato leaves contain solanine that deters asparagus beetle; planting tomatoes adjacent to permanent asparagus beds protects spear development from feeding damage.","strength":"moderate","source":"Cornell Cooperative Extension; Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"berseem-clover-bigbee","type":"beneficial","mechanism":"nitrogen_fixing","description":"Berseem clover Bigbee winter-grown in Florida and Gulf coast supplies 100 lb N per acre and terminates easily ahead of spring tomato transplant.","strength":"moderate","source":"University of Florida IFAS berseem clover"},{"crop":"tomato","companion":"berseem-clover-frosty","type":"beneficial","mechanism":"nitrogen_fixing","description":"Frosty berseem tolerates light freezes so it holds biomass through Florida winter, then terminates at bloom for in-place N mulch for spring-planted tomato.","strength":"moderate","source":"University of Florida IFAS berseem clover"},{"crop":"tomato","companion":"cover-crop-mix-soil-builder","type":"beneficial","mechanism":"nitrogen_fixing","description":"Soil builder mix combining legume and small grain components leaves a 50:50 N and biomass balance that decomposes evenly under tomato over a 12 week fruiting window.","strength":"moderate","source":"USDA-SARE Managing Cover Crops Profitably mixes"},{"crop":"tomato","companion":"marigold","type":"beneficial","mechanism":"pest_repellent","description":"French marigolds (Tagetes patula) produce alpha-terthienyl and other thiophene compounds in their roots that suppress root-knot nematodes (Meloidogyne spp.). The strongest empirically-supported companion-planting effect known. Plant 12-18 inches from tomato roots.","strength":"strong","source":"UC ANR; USDA-ARS nematology research"},{"crop":"tomato","companion":"marigold-signet","type":"beneficial","mechanism":"pest_repellent","description":"Signet marigolds (Tagetes tenuifolia) repel whitefly and aphids and provide some nematode suppression, though less than French marigolds. Edible flowers double as garnish.","strength":"moderate","source":"UC ANR Master Gardener publications"},{"crop":"tomato","companion":"nasturtium","type":"beneficial","mechanism":"trap_crop","description":"Nasturtium attracts aphids and whiteflies away from tomato plants as a sacrificial host. Spray nasturtium with insecticidal soap to kill the aphid colony before it spreads back to the tomatoes.","strength":"moderate","source":"Cornell Cooperative Extension; Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"borage","type":"beneficial","mechanism":"pollinator_attractor","description":"Borage flowers attract bumblebees and honey bees that improve tomato fruit set through buzz pollination. Reputed to deter tomato hornworm; folklore claims flavor improvement.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"parsley-flat","type":"beneficial","mechanism":"pollinator_attractor","description":"Parsley flowers (in its second biennial year) attract parasitic wasps and hoverflies that prey on tomato hornworm and aphids.","strength":"moderate","source":"Cornell Cooperative Extension; Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"onion","type":"beneficial","mechanism":"pest_repellent","description":"Onion beds adjacent to tomato deter aphids and some leaf miners via sulfur compound volatiles.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"garlic-chive","type":"beneficial","mechanism":"pest_repellent","description":"Garlic chive (Allium tuberosum) provides milder allium deterrence than bulb garlic; less root competition with tomato. Perennial border option.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"yarrow","type":"beneficial","mechanism":"pollinator_attractor","description":"Yarrow's flat umbel flowers attract hoverflies (Syrphidae) and parasitic wasps that prey on tomato hornworm and aphids. Drought-tolerant perennial — plant in bed corners.","strength":"moderate","source":"Xerces Society pollinator habitat publications"},{"crop":"tomato","companion":"calendula","type":"beneficial","mechanism":"pollinator_attractor","description":"Calendula's bright orange composite flowers attract hoverflies and bees; minor pest-deterrent claims for whitefly.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"mint-spear","type":"beneficial","mechanism":"pest_repellent","description":"Mint deters whitefly and aphids near tomatoes. Always grow in containers around the tomato bed — never plant runners directly.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"crimson-clover","type":"beneficial","mechanism":"nitrogen_fixing","description":"Crimson clover winter cover crop tilled or rolled in spring releases substantial nitrogen for the tomato crop; reduces synthetic fertilizer needs by 30-50% in trials.","strength":"strong","source":"Cornell Cooperative Extension cover crop guides; SARE"},{"crop":"tomato","companion":"hairy-vetch","type":"beneficial","mechanism":"nitrogen_fixing","description":"Hairy vetch winter cover crop fixes 100-150 lb N/acre; rolled or tilled before tomato transplant, no-till tomato production with vetch residue mulch is a documented yield-boost technique.","strength":"strong","source":"SARE Cover Crops field guide; USDA-ARS Beltsville no-till research"},{"crop":"tomato","companion":"phacelia","type":"beneficial","mechanism":"pollinator_attractor","description":"Tomato is self-pollinating but bumblebee buzz-pollination significantly improves fruit set, especially in cool maritime climates. Phacelia draws those bumblebees.","strength":"moderate","source":"Xerces Society pollinator habitat publications"},{"crop":"tomato","companion":"cilantro","type":"beneficial","mechanism":"pollinator_attractor","description":"Cilantro (when bolted) attracts hoverflies and parasitic wasps that prey on aphids. Let some cilantro flower for the beneficials, save the seed as coriander.","strength":"moderate","source":"Cornell Cooperative Extension; Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"bee-balm","type":"beneficial","mechanism":"pollinator_attractor","description":"Native bee balm (Monarda fistulosa, M. didyma) attracts bumblebees whose buzz pollination boosts tomato fruit set; also attracts hummingbirds and beneficial wasps. Long bloom season.","strength":"moderate","source":"Xerces Society pollinator habitat publications"},{"crop":"tomato","companion":"garlic","type":"beneficial","mechanism":"pest_repellent","description":"Garlic interplanted with tomato deters aphids, spider mites, and some leaf miners through sulfur compound volatiles. Plant cloves at the corners of tomato cages in fall for spring harvest before tomatoes fill out.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"leek","type":"beneficial","mechanism":"pest_repellent","description":"Leek allium volatiles deter aphids and thrips near tomato, with less bulb root competition than full-size onion.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"shallot","type":"beneficial","mechanism":"pest_repellent","description":"Shallot deters aphids, leaf miners, and thrips near tomato through sulfur compound volatiles; smaller bulb fits tight spacing.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"chive","type":"beneficial","mechanism":"pest_repellent","description":"Chive border deters aphids and spider mites near tomato; perennial allium that flowers early for pollinators.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"zinnia","type":"beneficial","mechanism":"pollinator_attractor","description":"Zinnia attracts butterflies, native bees, and hummingbirds; bumblebees drawn by zinnia improve tomato buzz pollination and fruit set.","strength":"moderate","source":"Xerces Society pollinator habitat publications"},{"crop":"tomato","companion":"cosmos","type":"beneficial","mechanism":"pollinator_attractor","description":"Cosmos attracts hoverflies, lacewings, and parasitic wasps that prey on tomato hornworm and aphids; long bloom window through tomato fruit set.","strength":"moderate","source":"Xerces Society pollinator habitat publications"},{"crop":"tomato","companion":"sweet-alyssum","type":"beneficial","mechanism":"pollinator_attractor","description":"Sweet alyssum draws hoverflies whose larvae are top aphid predators near tomato; UC ANR trials show measurable aphid suppression with alyssum interplanting.","strength":"strong","source":"UC ANR; Xerces Society pollinator habitat publications"},{"crop":"tomato","companion":"winter-rye","type":"beneficial","mechanism":"ground_cover","description":"Winter rye cover crop terminated and rolled in spring forms a thick mulch; no-till tomato transplants into the rye residue see improved moisture retention and reduced early blight splashback. Standard in organic systems.","strength":"strong","source":"SARE Cover Crops field guide; USDA-ARS Beltsville no-till research"},{"crop":"tomato","companion":"daikon-cover","type":"beneficial","mechanism":"ground_cover","description":"Daikon cover (tillage radish) bio-drills compacted subsoil; deep taproots winter-kill in zones 7 and colder, leaving open channels and decomposing organic matter that improves drainage for spring tomatoes.","strength":"moderate","source":"SARE Cover Crops field guide"},{"crop":"tomato","companion":"lemon-balm","type":"beneficial","mechanism":"pest_repellent","description":"Lemon balm citral and citronellal volatiles deter aphids and whiteflies near tomato; bonus, flowering lemon balm attracts honeybees.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"tarragon","type":"beneficial","mechanism":"pest_repellent","description":"French tarragon's anise-like volatiles deter aphids and whiteflies near tomato; perennial in zones 5-9.","strength":"moderate","source":"Cornell Cooperative Extension"},{"crop":"tomato","companion":"marigold-african-crackerjack","type":"beneficial","mechanism":"pest_repellent","description":"African marigold (Tagetes erecta) produces alpha-terthienyl-class thiophenes effective against root-knot nematodes around tomato; taller habit than French marigold.","strength":"strong","source":"UC ANR; USDA-ARS nematology research"},{"crop":"tomato","companion":"lacy-phacelia","type":"beneficial","mechanism":"pollinator_attractor","description":"Lacy phacelia (Phacelia tanacetifolia, distinct slug from generic phacelia) is among the top bumblebee plants known; bumblebee buzz pollination improves tomato fruit set in cool maritime climates.","strength":"strong","source":"Xerces Society pollinator habitat publications"},{"crop":"tomato","companion":"berseem-clover","type":"beneficial","mechanism":"nitrogen_fixing","description":"Berseem clover (Trifolium alexandrinum) fixes nitrogen quickly and tolerates frequent mowing as a living mulch between tomato rows; standard organic mid-Atlantic rotation.","strength":"moderate","source":"SARE Cover Crops field guide"},{"crop":"tomato","companion":"buckwheat","type":"beneficial","mechanism":"pollinator_attractor","description":"Buckwheat strips alongside tomato draw hoverflies and parasitoid wasps that prey on aphids and tomato hornworm; bonus quick weed suppression.","strength":"strong","source":"SARE Cover Crops field guide; Xerces Society"}],"antagonists":[{"crop":"tomato","companion":"potato","type":"antagonist","mechanism":"disease_vector","description":"Same disease sharing as potato → tomato. Either direction concentrates blight, early blight, and Verticillium pathogens in the soil.","strength":"strong","source":"Cornell Cooperative Extension; Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"fennel-florence-zefa-fino","type":"antagonist","mechanism":"allelopathic","description":"Reverse-direction: tomato yields suppressed when grown within 4 ft of fennel due to fennel root exudate effect on tomato hormone signaling.","strength":"strong","source":"USDA-ARS allelopathy publications"},{"crop":"tomato","companion":"pepper-sweet","type":"antagonist","mechanism":"disease_vector","description":"Tomato and bell pepper share Verticillium, early blight, and tobacco mosaic virus. Avoid same-bed interplanting and rotate at minimum 3 years apart on the same ground.","strength":"moderate","source":"Cornell Cooperative Extension nightshade rotation"},{"crop":"tomato","companion":"eggplant","type":"antagonist","mechanism":"disease_vector","description":"Same Solanaceae family. Shared susceptibility to Verticillium, root knot nematode, and Colorado potato beetle. Rotate at minimum 3 years apart.","strength":"moderate","source":"Cornell Cooperative Extension nightshade rotation"},{"crop":"tomato","companion":"fennel-herb","type":"antagonist","mechanism":"allelopathic","description":"Fennel produces anethole and other allelopathic compounds that inhibit germination and growth of nearby crops; tomato is severely affected. Plant fennel in its own bed at the property edge.","strength":"strong","source":"Cornell Cooperative Extension; Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"fennel-bulb","type":"antagonist","mechanism":"allelopathic","description":"Florence fennel exhibits the same allelopathic effects as herb fennel — anethole and related volatiles inhibit tomato growth.","strength":"strong","source":"Cornell Cooperative Extension; Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"wormwood","type":"antagonist","mechanism":"allelopathic","description":"Wormwood (Artemisia absinthium) produces absinthin and santonin — powerful allelopathic compounds. Keep wormwood well away from vegetable beds; minimum 6 ft separation.","strength":"moderate","source":"Cornell Cooperative Extension; Riotte, Carrots Love Tomatoes"},{"crop":"tomato","companion":"kohlrabi","type":"antagonist","mechanism":"nutrient_competition","description":"Kohlrabi and tomato compete heavily for soil potassium and calcium; observed yield reduction on both crops when planted in the same bed.","strength":"moderate","source":"Cornell Cooperative Extension; Cunningham, Great Garden Companions"},{"crop":"tomato","companion":"walnut-black","type":"antagonist","mechanism":"allelopathic","description":"Black walnut (Juglans nigra) roots, leaves, and nut hulls release juglone (5-hydroxy-1,4-naphthoquinone), which is highly toxic to tomato. Symptoms include wilting and yellowing within the dripline plus 20-30 ft beyond. Never plant tomato within 50-80 ft of a mature black walnut.","strength":"strong","source":"USDA Forest Service juglone toxicity research; Penn State Extension; OSU Extension"},{"crop":"tomato","companion":"walnut-english","type":"antagonist","mechanism":"allelopathic","description":"English walnut (Juglans regia) produces less juglone than black walnut but still affects sensitive crops; keep tomatoes at least 30 ft from mature trees.","strength":"moderate","source":"USDA Forest Service juglone toxicity research"}]}