Tomatillo
Tomatillo is a vegetable in the Solanaceae family. It grows best in full sun with medium moisture, and is listed for USDA zones 2-13. Plants reach harvest about 51–98 days after planting.
Varieties
7 from High Mowing, True Leaf Market & Seeds Now · sorted by days to maturity▸Toma Verde Tomatillo51–69 days
Semi-determinate; Uniform fruit
Early variety with tart flavor when young, becoming sweeter as it ripens. Medium to large size fruits are ready to harvest when husks split and fruit color changes from a yellow green to medium green. Perfect for salsa verde or as a special addition to any Mexican dish. Physalis philadelphica Roma VF Granadero F1 Plum Perfect F1 Plum Regal F1 Amish Paste San Marzano Gilbertie Toma Verde Tomatillo
Growing notes: Days to maturity are from transplant. Tomatoes are warm-season tender annuals in the Solanaceae family. Indeterminate types ripen mid-to-late summer, bear fruit over a long period of time and require pruning and support. Determinate types ripen early, have a concentrated fruit set, shorter growth habit, and support may not be required. Start seeds 6-8 weeks before planting date. Optimal soil temperature for germination is 75-85°F. Transplant after danger of frost has passed. Harvest tomatoes fully ripe or when half ripe and ripen off the vine at temperatures above 70°F. Store between 55-70°F with 95% relative humidity.
View on High Mowing ↗▸Toma Verde59–81 days
Heirloom; Non-GMO; Vegetable; Annual
70 days. Physalis ixocarpa. Toma Verde Tomatillo Seeds. Non-GMO, annual, heirloom, open-pollinated. This crop is suitable for containers, garden plots, raised beds, and fields. Early, prolific green tomatillo with flat-round fruits in papery husks—ideal for salsa verde and roasting; plants tolerate heat and dry spells and set heavily. ~10,000 seeds/oz.
View on True Leaf Market ↗▸Grande Rio Verde68–92 days
Heirloom; Vegetable; Annual
80 days. (Husk Tomato) Large fruited tomatillo with sweet green fruits measuring 2 to 3 inches across (1.8 - 2.8 ounces), enclosed in a papery husk. Vigorous prostrate vine. Used in salsa verde or in pies. Good disease resistance. Approx. 10,000 seeds/oz.&
View on True Leaf Market ↗▸Grande Rio Verde (Organic)71–95 days
Heirloom / Open Pollinated; Vegetable; Annual; USDA certified organic seeds
Physalis ixocarpa (83 days) This var. produces the most and the largest tomatillos! Grande yields about a 3 oz green tomatillos. Great for salsa verde!
View on True Leaf Market ↗▸Classic72–98 days
Can tolerate hot temperatures; Direct sow; Grows well in full sun; Grows well with containers; Grows well with raised beds; Matures in <90 days; Start indoors; Super easy to grow
These tomatillo seeds will produce delicious 3-5 ounce fruits. Tomatillo is popularly used to make salsas. Days to Maturity | 85 days
View on Seeds Now ↗▸Purple72–98 days
Can tolerate hot temperatures; Direct sow; Grows well in full sun; Grows well with containers; Grows well with raised beds; Matures in <90 days; Start indoors; Super easy to grow
These tomatillo seeds will produce delicious 3-5 ounce fruits. Tomatillo is popularly used to make salsas. Days to Maturity | 85 days Grow vibrant purple tomatillos in your vegetable garden with these premium seeds. Each plant produces abundant 3-5 ounce fruits perfect for homemade salsas and authentic Mexican cuisine. These tomatillos mature in approximately 85 days, giving you a reliable harvest window. Plant in full sun with well-draining soil for best results. A must-have for gardeners seeking flavorful, prolific plants that thrive in warm seasons. Purple tomatillos are a gardener's delight, delivering tangy, versatile fruits ideal for fresh salsas and cooked dishes. These seeds produce plants that yield abundant 3-5 ounce fruits with a distinctive tart flavor that brightens any recipe. Reaching maturity in 85 days, they're perfect for warm-season gardens. Plant in full sun with good drainage and watch them thrive. Whether you're a salsa enthusiast or adventurous cook, purple tomatillos add authentic flavor and visual appeal to your harvest.
View on Seeds Now ↗▸Verde72–98 days
Can tolerate hot temperatures; Direct sow; Grows well in full sun; Grows well with containers; Grows well with raised beds; Matures in <90 days; Start indoors; Super easy to grow
The Verde Tomatillo plant produces medium 3 ounce fruits Tomatillo is popularly used to make salsas Days to Maturity | 85 days
View on Seeds Now ↗
Plan your tomatillo planting
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Storing & preserving
Most keep best refrigerated; storage crops prefer a cool, dry spot.
- Freeze: Blanch briefly, cool, then freeze — keeps color and texture.
- Can: Pressure-can low-acid vegetables; water-bath only pickled/acidified ones.
General home-preservation guidance — for tested processing times and safety, follow the National Center for Home Food Preservation.
Growing timeline
Companion planting — with cited sources
From US/Canada cooperative-extension publications and peer-reviewed studies. Evidence-tier dots show how strongly each recommendation is backed: ●●● peer-reviewed mechanism · ●● extension consensus · ● traditional knowledge with a plausible mechanism.
Pairs well with (24)
- French MarigoldEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismpest-deter
Tagetes patula releases alpha-terthienyl from roots, a thiophene with peer-reviewed nematicidal activity against root-knot nematode (Meloidogyne incognita and related species). T. patula also emits airborne limonene shown in PLOS One trials to deter glasshouse whitefly from tomato. Most reliable when grown as a solid cover the prior season, but interplanting still gives a partial benefit. Tagetes patula suppresses root-knot nematode populations on Solanaceae roots.
Timing: Full-season marigold cover the prior year is the strongest single treatment.
Region: Most valuable in zones 7+ and high tunnels with established root-knot nematode populations.
- AsparagusEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpest-deter
Asparagus roots contain asparagine and associated compounds with reported activity against the root-knot nematode (Meloidogyne spp.), to which tomato is highly susceptible. Several extension sources (Cornell, Iowa State) endorse the tomato-asparagus pairing on this basis, though field-trial data are thin. Tomato is also said to repel asparagus beetle, but evidence for this is weaker.
Timing: Plant tomatoes at one end of an asparagus bed where they won't shade the asparagus fern.
- Bay LaurelEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpest-deter, flavor-folklore
Bay laurel is sometimes interplanted in Mediterranean kitchen gardens; the essential oils (eucalyptol, linalool) have mild lab-demonstrated repellency against some stored-product insects, but field evidence for tomato pest deterrence is absent. Tier C.
Region: Mediterranean climate gardens (CA).
Source: UC IPM
- Bee BalmEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract, predator-attract
Monarda didyma flowers attract bees, hummingbirds, and parasitic wasps that prey on tomato hornworm; recommended as a perennial bed-edge companion in Cornell and Penn State home-garden guides. Susceptible to powdery mildew — choose resistant cultivars.
Region: Eastern North America native; thrives zones 4-9.
Source: S1, Penn State Extension
- BorageEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract, predator-attract
Borage (Borago officinalis) attracts bumblebees and other pollinators that buzz-pollinate tomato flowers, and attracts predatory insects (lacewing, syrphid) that help suppress tomato pests. Documented in UMN and Cornell home-garden guides; field-trial evidence specific to yield effect is limited.
- BuckwheatEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract, predator-attract
Buckwheat strips between tomato beds host Syrphid flies and minute pirate bugs (Orius spp.) that prey on thrips and aphids. Used as an in-season insectary strip in Northeast organic tomato systems.
Timing: Stagger 2-3 sowings 2 weeks apart to keep continuous bloom.
Source: S1, Penn State Extension, SARE
- CarrotEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationflavor-folklore
Carrot / tomato is a long-standing folk pairing without a clearly replicated mechanism. The crops have non-overlapping rooting depths and tomato canopy can provide light shade during midsummer heat. Tier C with flavor-folklore tag.
Source: University of Maryland Extension
- CilantroEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpredator-attract, pollinator-attract
Flowering cilantro is documented to elevate natural-enemy abundance (syrphids, lacewings, parasitoids) in tomato beds, contributing to aphid and hornworm suppression.
- Common BeanEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationn-fixation
Bush bean interplanting between tomato plants contributes modest residual N from nodule turnover and post-season residue. Effect on same-season tomato yield is small; primarily helps the following crop.
Source: University of Maryland Extension
- Common CeleryEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationflavor-folklore
Celery / tomato is a long-standing folk pairing with no replicated mechanism beyond shared cultural requirements (full sun, steady moisture, rich soil). Included for completeness; tier C with flavor-folklore tag.
Source: University of Maryland Extension
- Common ChivesEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpest-deter
Chive perimeter or interplant is widely cited by extension references as deterring aphids on tomato; effect is plausible (volatile masking) but field-trial evidence is thin.
Source: University of Maryland Extension, S13
- Common NasturtiumEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationtrap-crop, pollinator-attract
Nasturtium near tomato is traditionally recommended for aphid trapping and pollinator support; pollinator benefit is well-supported, aphid trap-cropping in tomato is less studied than in cucurbits/beans.
Source: University of Maryland Extension
- Common ParsleyEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpredator-attract, pollinator-attract
Allowed-to-bolt parsley provides accessible nectar for syrphid flies, lacewings, and small parasitoid wasps that suppress aphids and hornworm eggs in tomato. The pairing is a long-standing extension home-garden recommendation; mechanism is plausible, replication is modest.
Timing: Best benefit comes when second-year (biennial) plants flower or when first-year plants are allowed to bolt.
Source: University of Maryland Extension, S13
- Common ThymeEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract, predator-attract
Thyme in flower supports parasitoids of tomato hornworm and aphids; bed-edge planting is a common recommendation.
Source: University of Maryland Extension
- DillEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpredator-attract
Young dill is reported by extension home-garden guides to attract Trichogramma wasps and other natural enemies of tomato hornworm. Many guides also recommend removing dill before it bolts because mature dill is reported to suppress tomato vigor.
Timing: Use as a young-plant companion; remove before flowering to avoid reported tomato growth suppression.
Source: University of Maryland Extension
- Greek Bush BasilEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpest-deter
Shares Ocimum basilicum volatile profile; same rationale and same evidence tier as sweet basil for tomato pest deterrence and bed-mate use.
Source: University of Maryland Extension, Bekele & Hassanali, 2001
- Holy BasilEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpest-deter, pollinator-attract
Holy basil (tulsi) shares the linalool/eugenol-rich volatile profile of Ocimum basilicum and is heavily visited by bees; same general companion guidance.
Source: University of Maryland Extension, Bekele & Hassanali, 2001
- Italian ParsleyEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpredator-attract
Same insectary role as common parsley; see common parsley for complete discussion.
Source: University of Maryland Extension, S13
- Lemon BalmEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract, predator-attract
Lemon balm supports parasitoid wasps and small predators that attack tomato hornworm and aphids; mechanism plausible but field replication limited.
Source: University of Maryland Extension
- Lemon VerbenaEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract, flavor-folklore
Lemon verbena is a common kitchen-garden herb companion. The citral-rich foliage is sometimes claimed to deter insects, but empirical support is weak; pollinator attraction during bloom is real. Mostly traditional practice with weak mechanism.
Source: S11
- Mexican Mint MarigoldEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract, predator-attract
Tagetes lucida flowers attract bees and predatory insects; lacks the strong α-terthienyl nematicidal activity that distinguishes T. patula and T. erecta, but provides general insectary value.
Source: S11
- New Zealand SpinachEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationweed-suppression, moisture-conservation
New Zealand spinach makes a heat-tolerant summer leafy green and is sometimes used as a living groundcover under widely spaced tomato trellises; it suppresses weeds and conserves moisture and is harvested through the heat of summer when true spinach has bolted. Mechanism plausible; specific replicated extension data limited.
Source: S1
- Pot MarigoldEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpredator-attract
Calendula is recommended as an insectary plant in tomato rows; supports hoverflies and small parasitoid wasps that attack aphids and small caterpillars.
Source: University of Maryland Extension
- Sweet BasilEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpest-deter, pollinator-attract, flavor-folklore
Basil (Ocimum basilicum) leaf volatiles (eugenol, linalool, methyl chavicol) have laboratory-documented deterrent activity against thrips, aphids, and whiteflies, with limited but supportive field results from Iowa State, University of Minnesota, and West Virginia extension trials. Basil flowers also attract pollinators and parasitic wasps. Folk claims that basil improves tomato flavor are unverified and tagged separately. Long-standing folk claim that basil improves tomato flavor in the field. No empirical support, but listed honestly because the claim is too widespread to silently omit.
Source: S7, Eliot Coleman, Bekele & Hassanali, 2001
Avoid planting near (39)
- Black WalnutEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismallelopathy-negative
Juglone produced by Juglans nigra roots, leaves and hulls causes wilt, stunting, and death in tomato. Effects extend roughly to the dripline and beyond. Iowa State, Michigan State, and University of Wisconsin extension all list tomato among the most sensitive vegetables. Standard mitigation is raised beds with root barriers and removal of walnut leaf litter.
Region: Anywhere Juglans nigra is in the landscape: eastern and midwestern US, southern Canada.
- Common PotatoEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismdisease-host, alternate-host-pest
Tomato and potato share late blight (Phytophthora infestans) and serve as alternate hosts for each other's pathogen spores; they also share Colorado potato beetle, early blight (Alternaria), and Verticillium wilt. UMN Extension explicitly recommends not planting tomatoes where tomatoes, potatoes, peppers, or eggplants have been in the past 3-4 years. Adjacent same-season planting greatly accelerates spread of an outbreak in either crop.
Timing: Maintain 3-4 year rotation interval; physically separate beds within the same garden.
Source: Penn State Extension, S7
- StrawberryEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismdisease-host
Shared Verticillium wilt susceptibility. Avoid planting strawberry after tomato in the same bed for at least 3 years.
- Ají PepperEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Shares Solanaceae disease and pest complex with tomato. Group in rotation but do not interplant in adjacent rows.
Source: S7
- ButternutEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsallelopathy-negative
Butternut produces juglone at lower concentrations than black walnut but still measurable; sensitive species (Solanaceae, blueberry, ericaceous shrubs) can be affected within the dripline.
- Cape GooseberryEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Cape gooseberry shares the Solanaceae pest/disease complex with tomato, including three-lined potato beetle, Colorado potato beetle, and Verticillium wilt.
Source: Penn State Extension
- Cayenne PepperEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Cayenne shares the full Solanaceae disease and pest complex with tomato and potato (Phytophthora, Verticillium, tobacco mosaic virus, Colorado potato beetle, hornworms). Treat cayenne the same as bell/hot pepper in spacing and rotation.
Source: S7, University of Maryland Extension
- Common EggplantEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Tomato and eggplant share early blight, Verticillium, and bacterial spot. Rotate as a Solanaceae group rather than alternating in adjacent rows.
Source: S7, University of Maryland Extension
- Common TomatoEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Currant tomato is closely related to S. lycopersicum and shares the full Solanaceae pest/disease complex. Same rotation and adjacency rules apply.
Source: S7
- CornEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsalternate-host-pest
Corn earworm and tomato fruitworm are the same species (Helicoverpa zea); moths emerging from corn move readily to tomato fruit. Avoid contiguous plantings or stagger to break the cycle.
Timing: Separate corn and tomato by at least 6-9 m or stagger plantings so silking corn and fruiting tomato do not overlap.
Region: Pressure increases from north to south; severe in the South and Mid-Atlantic.
Source: Penn State Extension, S11, UC IPM Pest Notes
- Currant TomatoEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Currant tomato is closely related to S. lycopersicum and shares the full Solanaceae pest/disease complex. Same rotation and adjacency rules apply.
Source: S7
- English WalnutEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsallelopathy-negative
English walnut produces juglone at lower concentrations than black walnut, but enough to affect highly sensitive species (Solanaceae, blueberry, ericaceous shrubs) within the dripline. Most commercial English walnut in CA is grafted on black walnut rootstock, which also exudes juglone from roots — so the AVOID list is functionally the same as for black walnut.
Region: California Central Valley walnut orchards; effect more pronounced where black walnut rootstock is used.
- Ground CherryEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Ground cherry (Physalis pruinosa) is host to three-lined potato beetle and shares Verticillium and Phytophthora susceptibility with tomato.
Source: Penn State Extension, S7
- Habanero PepperEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Shares the Solanaceae disease/pest complex with tomato. Rotate as a group, do not co-plant in adjacent rows.
Source: S7
- Hot PepperEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Hot pepper shares Solanaceae disease and pest complex with tomato (bacterial spot, Phytophthora, hornworms, aphids). Group with tomato in rotation but do not alternate them in adjacent rows year-on-year.
Source: S7, University of Maryland Extension
- Japanese WalnutEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsallelopathy-negative
All Juglans species produce juglone (5-hydroxy-1,4-naphthoquinone) to varying degrees. Japanese walnut and its butternut hybrid 'heartnut' produce juglone at levels intermediate between black walnut and English walnut — enough to affect sensitive species (Solanaceae, blueberry) within the dripline.
- Jerusalem ArtichokeEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsallelopathy-negative, nutrient-competition
Same rationale as for bean; sunchoke crowds and shades adjacent crops and is hard to eradicate once established.
Source: S7
- PeanutEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host
Peanut and tomato share susceptibility to Sclerotium rolfsii (southern blight) and several Fusarium and Rhizoctonia species. Sequential or adjacent plantings can build up shared soilborne inoculum.
Region: Warm humid regions (zones 7+).
Source: S11
- PeppermintEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsnutrient-competition
Same competition warning as spearmint — never plant peppermint directly in the bed with annual vegetables.
Source: University of Maryland Extension
- Rocoto PepperEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Companion interactions equivalent to other domesticated Capsicum spp.; rocoto shares the Solanaceae disease/pest complex with tomato. Note rocoto requires cooler summer nights than other peppers, so it is grown at small scale in coastal Pacific Northwest and high elevation only.
Region: Limited US production: Pacific Northwest, high-elevation regions.
Source: S4
- SpearmintEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsnutrient-competition
Mint's aggressive rhizomes outcompete tomato roots if planted directly in the bed. Use containers to keep volatile oils available without root invasion.
Source: University of Maryland Extension
- Sweet Bell PepperEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Peppers and tomatoes are both in Solanaceae and share major diseases (Phytophthora capsici, Verticillium wilt, bacterial spot, several mosaic viruses) and pests (aphids, flea beetles). Extension rotation guidance advises grouping Solanaceae but rotating the entire group off the bed for 3-4 years rather than alternating tomato and pepper in adjacent rows.
Source: S7, University of Maryland Extension
- Sweet PotatoEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Sweet potato and tomato share several pests including whitefly, southern root-knot nematode (Meloidogyne incognita), and tomato spotted wilt virus reservoirs. NC State recommends rotating sweet potato away from Solanaceae cash crops in nematode-prone soils.
Timing: Maintain ≥2-year rotation between sweet potato and Solanaceae.
Region: Southeast, especially sandy nematode-prone soils.
Source: S11, NC State Extension
- Tabasco PepperEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Shares Solanaceae disease/pest complex with tomato.
Source: S7
- TomatilloEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsdisease-host, alternate-host-pest
Tomatillo shares the full Solanaceae pest and disease complex with tomato (early blight, Phytophthora, hornworms, three-lined potato beetle which specifically targets tomatillo and Physalis). Rotate as a group, do not co-plant.
Source: Penn State Extension, S7
- BroccoliEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationnutrient-competition
Shared brassica/tomato conflict; see common cabbage.
Source: University of Maryland Extension
- Brussels SproutsEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationnutrient-competition
Shared brassica/tomato nutrient and pH conflict; see common cabbage.
Source: University of Maryland Extension
- Common CabbageEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationnutrient-competition, allelopathy-negative
Tomato and Brassica crops compete for the same shallow-zone N and Brassicas release glucosinolate-derived isothiocyanates that can stunt nearby Solanaceae. Most extension home-garden guides advise not interplanting tomatoes with cabbage/broccoli/kale, although controlled-trial evidence on the allelopathy mechanism in field conditions is limited.
Source: S7, University of Maryland Extension
- Common KaleEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationnutrient-competition
Shared brassica/tomato nutrient and pH conflict; see common cabbage for full discussion.
Source: University of Maryland Extension
- Downy Ground CherryEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationdisease-host, alternate-host-pest
As a Physalis species, shares the Solanaceae pest and disease complex with tomato; companion guidance equivalent to ground-cherry entry.
Source: Penn State Extension
- Florence FennelEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative
Same fennel allelopathy as sweet fennel; isolate Florence fennel in its own bed.
Source: University of Maryland Extension
- KohlrabiEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationnutrient-competition
Shared brassica/tomato conflict; see common cabbage.
Source: University of Maryland Extension
- OkraEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationalternate-host-pest, disease-host
Okra and tomato share several pests (stink bugs, root-knot nematode) and Verticillium susceptibility; Southern extension generally suggests not following tomato with okra in nematode-prone soils.
Region: Southeast.
Source: S11
- PecanEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative
Pecan produces juglone in lower concentrations than black walnut, but sensitive Solanaceae (tomato, pepper, eggplant) can still show stunting near mature pecan trees. UGA and Texas A&M note this as a soft caution rather than a strict avoidance.
Region: Southeast and Texas/Oklahoma pecan country.
Source: S11
- Romanesco Broccoli / CauliflowerEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationnutrient-competition
Calcium competition is especially relevant for cauliflower (susceptible to tip-burn / brown bead) — pairing with another heavy calcium feeder is discouraged. See common cabbage.
Source: University of Maryland Extension
- RutabagaEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationnutrient-competition
Shares the Brassicaceae / tomato avoidance flagged by extension references (calcium and nitrogen competition, soil-pH mismatch). See common cabbage for complete relationships.
Source: University of Maryland Extension
- Shagbark HickoryEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative
Same as shellbark: hickories produce juglone (lower than walnut) and sensitive Solanaceae can be affected within the dripline.
Source: S5
- Shellbark HickoryEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative
Hickories produce juglone in lower concentrations than walnut but enough to mildly affect sensitive species (tomato, pepper, eggplant, blueberry) within the dripline. Extension caution rather than firm avoidance.
Source: S5
- Sweet FennelEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative
Fennel (Foeniculum vulgare) releases anethole-related allelochemicals reported to stunt tomato and most vegetable neighbors. Listed across multiple extension companion-planting summaries.
Source: S7
Biofumigant cover crops (1)
- Cover MustardEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsbiofumigation
Mustard biofumigation ahead of tomato suppresses Verticillium and some root-knot nematode populations; documented in WSU and Cornell trials.
Timing: Incorporate at full bloom; wait 2-3 weeks before transplant.
Good successors in rotation (7)
- Cereal RyeEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismallelopathy-positive, weed-suppression, soil-conditioning
Cereal rye residues release benzoxazinoids (DIBOA, BOA) and short-chain phenolic acids that suppress small-seeded weeds for 4-10 weeks after termination. Transplanted tomato (large transplant, deep root) tolerates the residue while weeds are suppressed. SARE and Northeast Cover Crop Council document this as a foundational no-till tomato system.
Timing: Chemical allelopathy from rye benzoxazinoids declines in soil over ~2 weeks after termination (Rice et al., 2012 and Cornell-affiliated reviews); physical mulch suppression of weeds persists longer (4–10 weeks depending on residue mass). Direct-seeding of small-seeded crops should still wait ~3–4 weeks; transplanted tomato can typically go in 1–2 weeks after termination.
Region: Effective across the Northeast, Mid-Atlantic, and Midwest; less reliable in the deep South where rye biomass is lower.
Source: SARE, S29, Putnam, 1988
- Crimson CloverEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismn-fixation, weed-suppression
Fall-seeded crimson clover terminated in spring delivers 90-130 lb N/acre to the following tomato crop. Rodale's no-till tomato-into-rolled-crimson system is well documented and widely replicated.
Timing: Roller-crimp at full bloom; transplant tomato 1-2 weeks later.
Region: Reliable mid-Atlantic, Southeast, and Pacific Northwest.
Source: Rodale Institute, SARE, S29
- Hairy VetchEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismn-fixation, weed-suppression, disease-host
Hairy vetch is the foundational legume of no-till tomato systems: fixes 80-180 lb N/acre and the rolled mulch reduces foliar disease (Septoria, early blight) by ~20-40% via splash-block effect. USDA-ARS Beltsville (Abdul-Baki & Teasdale) documented yield improvements vs. bare-ground and black-plastic systems.
Timing: Roller-crimp at full bloom (mid-May mid-Atlantic); transplant tomato into rolled mulch within 1 week.
Region: Mid-Atlantic and Southeast best documented; zones 5-8.
- RyeEvidence tier A: Peer-reviewed studies in US/Canada production conditions with a clear mechanismweed-suppression, allelopathy-positive
Roll-crimped or mowed rye produces a thick mulch that suppresses weeds in transplanted tomato. Rodale's no-till tomato system is built on this practice; mid-Atlantic extension trials confirm.
Timing: Roll at anthesis (full pollen shed) for clean kill; transplant tomato through residue 1-2 weeks later.
Region: Mid-Atlantic, Northeast.
Source: Penn State Extension, Rodale Institute
- Fava BeanEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsn-fixation, soil-conditioning
Overwintered fava terminated in spring is a documented predecessor for heavy-feeding summer crops including tomato. Residual N and improved soil tilth benefit the following Solanaceae crop.
Timing: Terminate fava 2-3 weeks before tomato transplant to allow residue partial decomposition.
Region: Mild-winter regions where fall sowing is possible (PNW, coastal CA, mid-Atlantic).
Source: S4, Rodale Institute
- SorghumEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsweed-suppression, biofumigation, soil-conditioning
Sorghum-sudangrass summer cover ahead of fall-transplanted tomato or following spring tomato provides biomass, weed suppression, and root-knot nematode suppression in some trials. Transplanting (vs. seeding) avoids the allelopathic stand reduction.
Region: Mid-Atlantic, Southeast.
Source: Penn State Extension, S29
- Sorghum-SudangrassEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionsallelopathy-positive, weed-suppression, soil-conditioning
Sorghum-sudangrass roots exude sorgoleone, a potent allelochemical that suppresses small-seeded weeds and is implicated in nematode suppression (root-knot Meloidogyne spp., root-lesion Pratylenchus spp.). High biomass (5-8 tons/acre) builds soil organic matter. SARE and Cornell Soil Health document widely.
Timing: Mow when 3-4 ft tall to encourage rooting; terminate at frost; allow 3-4 weeks before transplanting following crop.
Region: Warm-season; requires soils >65°F at planting. Most useful in summer fallow windows in vegetable rotations.
Source: SARE, S29, Putnam, 1988
Sources cited
- S1
- Cornell University Cooperative Extension — vegetable production guides
- S10
- University of Wisconsin–Madison Extension
- S11
- University of Georgia Cooperative Extension
- S12
- NC State Extension
- S13
- University of New Hampshire Extension
- S16
- Cornell Climate Smart Farming / Cornell Small Farms
- S17
- Rodale Institute
- S18
- SARE (Sustainable Agriculture Research and Education)
- S20
- USDA ARS (Agricultural Research Service) publications
- S27
- Eliot Coleman — *The New Organic Grower*
- S28
- Bekele & Hassanali, 2001 — basil volatile bioassay
- S29
- Cornell Soil Health Lab / Northeast Cover Crop Council (NECCC)
- S3
- UC IPM (University of California Agriculture and Natural Resources)
- S33
- Putnam, 1988 — cereal rye allelopathy review
- S34
- UC IPM Pest Notes — specific pest pages
- S4
- Oregon State University Extension Service
- S5
- Michigan State University Extension
- S6
- Penn State Extension
- S7
- University of Minnesota Extension
- S8
- Iowa State University Extension and Outreach
- S9
- University of Maryland Extension — Home & Garden Info Center
Care & troubleshooting— extension-sourced, with citations
When to feed, prune & water
Attract beneficial insects and protect pollinators
Protection- Routine carePlant insectary flowers and tolerate light pestsstrong evidence — extension confidence
Grow a diversity of flowering plants (including small-flowered umbels and asters) to feed predators and parasitoids, and tolerate low pest numbers so natural enemies have prey to stick around.
- Routine careNever spray open bloomsstrong evidence — extension confidence
Avoid insecticides on flowering plants and apply any needed sprays in the evening when pollinators aren't active, and favor selective products over broad-spectrum ones to spare bees and beneficials.
Mulch to suppress weeds and retain moisture
Mulch- Routine careApply organic mulch around plantsstrong evidence — extension confidence
Spread a few inches of straw, shredded leaves, or compost around established plants (keeping it off stems) to hold soil moisture, suppress weeds, and moderate soil temperature; wait until soil has warmed for heat-loving crops.
Plan crop rotation
Rotation- Routine careRotate plant families between bedsstrong evidence — extension confidence
Avoid planting the same family in the same bed in consecutive years (aim for a 3+ year gap), grouping crops by family so soilborne diseases and pests that build up don't carry over to the next susceptible crop.
- Routine careSequence for soil healthmoderate evidence — extension confidence
Follow heavy feeders like tomatoes and brassicas with legumes or a cover crop to support soil fertility and structure, and keep simple notes each year so you can track where each family grew.
Protect the garden from deer
Protection- Routine careFence the gardenstrong evidence — extension confidence
A fence about 8 feet tall and tight to the ground is the most reliable barrier; an outward-angled or double fence, or monofilament line strung at 30 to 36 inches, can also deter deer on smaller beds.
- Routine careRotate repellents as a supplement· every 2 wksmoderate evidence — extension confidence
Where fencing isn't feasible, apply odor/taste repellents and alternate formulations, reapplying every couple of weeks and after rain; combining repellents with fencing works best.
Water deeply at fruiting
Watering- Routine careProvide steady deep watering during fruiting· every 3 daysstrong evidence — extension confidence
Once plants begin flowering and setting fruit, supply about 1 to 1.5 inches of water per week in deep soakings rather than light sprinkles, ideally at the base; even moisture reduces cracking, blossom-end rot, and bitter or misshapen fruit.
Clean up debris and sanitize at season end
SanitationUnusual this time of year.
- Routine careRemove spent plants and fallen debrisstrong evidence — extension confidence
Pull and clear old plants, dropped fruit, and leaf litter at season end, since many pests and diseases overwinter in this debris; dispose of diseased material rather than composting it.
- Routine careClean tools, stakes, and cagesmoderate evidence — extension confidence
Wash and sanitize stakes, cages, and tools that touched diseased plants before storing or reusing them to avoid carrying pathogens into next season.
Cutworm collars at transplant
ProtectionUnusual this time of year.
- Routine careSet a collar around each new transplantstrong evidence — extension confidence
When setting out transplants, slip a collar (a toilet-paper tube, paper cup with the bottom cut out, or similar) around each stem and press it a couple inches into the soil so it stands a few inches above ground, blocking cutworms from the stem.
Harden off seedlings
ProtectionUnusual this time of year.
- Routine careGradually expose plants to the outdoors· every 1 days · ~2 wksstrong evidence — extension confidence
Starting about two weeks before transplanting, set seedlings outside in a sheltered, shady spot for a few hours and lengthen their time and sun exposure each day, avoiding windy days, to prevent transplant shock.
- Routine careEase back on water and transplant on a mild daystrong evidence — extension confidence
Water a little less during hardening (without letting plants wilt) to toughen growth, then transplant in late afternoon or on a cool, cloudy, calm day.
Something looks wrong?
Describe what you see on your tomatilloand we'll rank the likely causes — most likely first, least-invasive fix first.
Bacterial soft rot
Diseasesevere- CulturalRemove rotting plants and produce (manage, not cure)strong evidence — extension confidence
Soft rot can't be cured once tissue breaks down; promptly remove and discard affected plants and produce so the bacteria don't spread to neighbors or other stored vegetables.
- CulturalAvoid wounds and excess moisturestrong evidence — extension confidence
Harvest in dry conditions, handle gently to avoid bruising, control insects that create entry wounds, and improve drainage; cure and store bulbs and roots cool and dry.
- CulturalDon't overwater and rotatemoderate evidence — extension confidence
Avoid waterlogged soil and overhead watering that splashes bacteria, and rotate away from previously affected fleshy crops to lower disease pressure.
Fusarium / Verticillium wilt
Diseasesevere- CulturalRemove the plant; rotate and choose resistant varietiesstrong evidence — extension confidence
There is no cure once a plant is infected. Pull it, avoid planting the same family there for 3-4 years, and grow V/F-resistance-coded varieties next season.
Late blight
Diseasesevere- CulturalRemove and bag infected plantsstrong evidence — extension confidence
Late blight is highly contagious and can wipe out a planting in days. Pull and bag (don't compost) symptomatic plants to protect neighbors and nearby gardens.
Phytophthora blight (root and crown rot)
Diseasesevere- CulturalRemove affected plants at first sign (manage, not cure)strong evidence — extension confidence
Infected plants can't be saved; promptly pull and destroy them at the start of an outbreak to slow spread, and avoid working in beds when wet.
- CulturalImprove drainage and avoid waterloggingstrong evidence — extension confidence
Plant on raised beds, never let beds stay saturated, and water with drip rather than flooding, since this water mold thrives in standing water and saturated soil.
- CulturalRotate and choose tolerant varietiesmoderate evidence — extension confidence
Rotate out of peppers, cucurbits, and tomatoes for at least three years where the disease has occurred, and select tolerant or resistant varieties when available.
Root-knot nematodes
Nematodesevere- CulturalConfirm with a soil test, then rotate (manage, not cure)strong evidence — extension confidence
Root-knot nematodes can't be eradicated from garden soil, so confirm via a county Extension nematode assay and rotate beds to non-hosts or resistant varieties (look for VFN-type resistance in tomato).
- CulturalPlant suppressive cover/rotation cropsmoderate evidence — extension confidence
A solid planting of French marigolds grown 2+ months and turned under, or cover crops such as sorghum-sudangrass or cowpea, can lower populations between susceptible crops.
- CulturalSanitation and organic mattermoderate evidence — extension confidence
Avoid moving infested soil on tools or transplants, build soil organic matter to support beneficial organisms, and keep plants well watered to help them tolerate root damage.
Southern blight
Diseasesevere- CulturalRemove infected plants and surrounding soil (manage, not cure)strong evidence — extension confidence
Once a plant collapses it can't be cured; dig out the plant plus the top few inches of nearby soil containing sclerotia and dispose of it, avoiding spread on tools.
- CulturalBury residue and rotatemoderate evidence — extension confidence
Deep-turn soil to bury sclerotia, remove crop debris at season end, and rotate susceptible solanaceous and legume crops with grasses for several seasons.
- CulturalAdjust soil pH and plant earlymoderate evidence — extension confidence
Maintain soil pH at the level recommended for the crop, since the disease is worse in low-pH soils, and time plantings so harvest begins before peak summer heat favors the fungus.
Tomato spotted wilt virus
Virussevere- CulturalRemove infected plants (cannot be cured)strong evidence — extension confidence
There is no cure once a plant is infected, so promptly pull and dispose of symptomatic plants to reduce the virus reservoir that thrips spread to healthy plants.
- CulturalStart clean and control weeds and thripsstrong evidence — extension confidence
Use virus- and thrips-free transplants, choose resistant varieties (Sw-5 tomatoes, Tsw peppers) where available, and control weeds around the garden that harbor both virus and thrips vectors.
White mold (Sclerotinia stem rot)
Diseasesevere- CulturalRemove infected plants (manage, not cure)strong evidence — extension confidence
There's no cure for an infected plant; cut out and bag affected plants including the black sclerotia, and don't compost them, since sclerotia survive years in soil.
- CulturalOpen the canopy and rotatestrong evidence — extension confidence
Space plants widely, control weeds, orient rows to prevailing wind, and avoid overhead watering at bloom to dry the canopy; rotate to non-host crops (corn or other grasses) for several years.
- CulturalWater at the base, not overheadmoderate evidence — extension confidence
Use drip or soaker irrigation to keep foliage and the soil surface drier, which discourages the sclerotia germination and mycelial growth that drive white mold.
Blister beetles
Pestmoderate- CulturalHand-pick wearing gloves· every 2 daysmoderate evidence — extension confidence
Wear gloves (these beetles release a blistering fluid) and knock beetles into soapy water, or use row cover ahead of swarms; their larvae eat grasshopper eggs, so tolerate light feeding when you can.
- OrganicSpot-treat heavy swarms· every 1 wkmoderate evidence — extension confidence
If a large swarm threatens a planting, a pyrethrin or other labeled insecticide can knock them back per the label; avoid spraying open blooms to protect pollinators.
Botrytis gray mold
Diseasemoderate- CulturalRemove infected tissue and old blossomsstrong evidence — extension confidence
Prune out moldy leaves, stems, and fruit and clear fallen blossoms and debris where the fungus gets started, disposing of them rather than composting.
- CulturalImprove airflow and reduce leaf wetnessstrong evidence — extension confidence
Space and stake plants for good air movement, water at the base in the morning, and harvest ripe fruit promptly so botrytis has fewer cool, humid, wet surfaces to colonize.
Damping-off (seedlings)
Diseasemoderate- CulturalDry out, ventilate, sow into clean mixstrong evidence — extension confidence
Use sterile seed-starting mix, bottom-water and let the surface dry between waterings, add airflow, and don't over-sow. Damping-off can't be cured once a seedling collapses.
Early blight
Diseasemoderate- CulturalRemove affected lower leavesstrong evidence — extension confidence
Pick off spotted leaves into the trash (not compost). Mulch heavily to stop soil splash and water at the base.
- CulturalPrune for airflowstrong evidence — extension confidence
Thin crowded interior foliage so leaves dry quickly after rain or dew.
- ChemicalCopper - label use only· every 1 wk · ~4 wksmoderate evidence — extension confidence
Only if established and spreading. Apply per label every 7-10 days; follow rates and pre-harvest intervals.
Herbicide drift damage (growth-regulator)
Disordermoderate- CulturalIdentify the source and protect future plantingsstrong evidence — extension confidence
Growth-regulator herbicides like 2,4-D and dicamba cause this distortion via drift or contaminated sprayers and mulch; identify and stop the source, and never use a sprayer that previously held herbicide on the garden.
- CulturalSupport recovery if exposure was lightmoderate evidence — extension confidence
Plants only lightly exposed (not directly sprayed) often outgrow the damage; keep them watered and lightly fed so they can push out normal new growth, though fruiting may be delayed.
Japanese beetles
Pestmoderate- CulturalHandpick into soapy water· every 1 days · ~4 wksstrong evidence — extension confidence
In early morning when beetles are sluggish, knock them into a bucket of soapy water; daily removal also reduces the scent that draws in more beetles. Skip the lure traps, which tend to attract more beetles than they catch.
- CulturalCover plants past bloommoderate evidence — extension confidence
On crops that have finished flowering and set fruit, drape a row cover or netting to keep beetles off without blocking pollination during bloom.
Potassium deficiency
Deficiencymoderate- CulturalConfirm with a soil test firststrong evidence — extension confidence
Edge scorch on older leaves has several causes, so get a soil test before adding potassium; over-applying can lock out magnesium and calcium.
- OrganicApply potassium per soil-test guidancemoderate evidence — extension confidence
If the test confirms low potassium, apply a potassium source (such as sulfate of potash) at the labeled/test-recommended rate and keep watering even, since drought worsens uptake.
Root rot from overwatering / poor drainage
Diseasemoderate- CulturalLet soil drain and water lessstrong evidence — extension confidence
Water root rots like Pythium thrive in saturated soil, so cut back watering, let the surface dry between irrigations, and water at the base rather than keeping soil constantly wet.
- CulturalImprove drainage and aerationstrong evidence — extension confidence
Use raised beds, loosen compacted soil, and add organic matter to improve drainage; remove plants that are already rotted since affected roots won't recover.
Spider mites
Pestmoderate- CulturalHose down and raise humidity· every 3 days · ~2 wksstrong evidence — extension confidence
Mites thrive in hot, dry, dusty conditions. Spray foliage (especially undersides) with water to dislodge them and reduce dust.
- OrganicInsecticidal soap or horticultural oil - label use only· every 5 days · ~2 wksmoderate evidence — extension confidence
Apply to undersides per label; mites resist many products, so soaps/oils are preferred. Not in extreme heat.
Stink bugs (brown marmorated and native)
Pestmoderate- CulturalExclude with row cover and clear nearby weedsstrong evidence — extension confidence
Cover susceptible crops with floating row cover before bugs arrive, and remove weeds and groundcover near the garden in early spring where stink bugs feed before moving to crops. Lift covers on flowering crops that need pollination.
- CulturalHand-pick bugs and egg masses· every 3 daysstrong evidence — extension confidence
Scout in the morning and drop adults, nymphs, and egg clusters into a bucket of soapy water; regular hand-picking keeps low populations in check since most garden insecticides work poorly on adults.
- OrganicSpot-treat young nymphs if numbers climb· every 1 wkmoderate evidence — extension confidence
If small nymphs are abundant, a botanical such as pyrethrin or azadirachtin, or insecticidal oil, may give some suppression per the label; adults are largely unaffected, so rely mainly on exclusion and hand-picking.
Thrips on fruiting vegetables
Pestmoderate- CulturalRemove weed and crop reservoirsstrong evidence — extension confidence
Control flowering weeds in and around the garden and remove spent host crops promptly, since thrips build up on these and move onto fruiting vegetables; avoid planting next to onions, garlic, or cereals where thrips numbers spike.
- CulturalKeep plants vigorous and rinse foliagemoderate evidence — extension confidence
Water and feed adequately so plants tolerate feeding, and a forceful water spray can knock down populations; reflective mulch can also deter thrips from settling on young plants.
- OrganicTreat with spinosad or oil if needed· every 1 wkmoderate evidence — extension confidence
If thrips are damaging growing points or fruit, spinosad or insecticidal soap/oil can help per the label; rotate modes of action and avoid spraying open blooms to protect pollinators and natural enemies.
Tomato hornworm
Pestmoderate- CulturalHand-pick (leave parasitized ones)· every 2 days · ~3 wksstrong evidence — extension confidence
Pick hornworms by hand at dusk. If one is covered in white rice-like cocoons, leave it - those are beneficial parasitic wasps doing your work.
- OrganicBt - label use only· every 1 wk · ~2 wksmoderate evidence — extension confidence
For heavy infestations, Bt kurstaki per label targets the caterpillars.
Whiteflies
Pestmoderate- CulturalRemove infested leaves and hose off· every 4 daysmoderate evidence — extension confidence
Pick off and discard heavily infested lower leaves and rinse colonies off undersides with a strong spray of water; yellow sticky cards help monitor numbers.
- OrganicApply a labeled soap or oil· every 1 wk · ~3 wksmoderate evidence — extension confidence
Apply a labeled insecticidal soap or neem oil per the label, covering leaf undersides; these reduce but won't eliminate whiteflies, so repeat as needed.
Cutworms
PestmoderateUnusual this time of year.
- CulturalPlace stem collars on transplantsstrong evidence — extension confidence
Push a collar (cardboard tube, can, or cup with bottom removed) a couple inches into the soil around each stem so it extends a few inches above ground; this blocks cutworms from reaching the stem.
- CulturalScout soil and hand-remove· every 3 days · ~2 wksstrong evidence — extension confidence
In the evening or early morning, check the soil around damaged plants and remove curled larvae by hand; tilling beds about two weeks before planting also reduces larvae and pupae.
- OrganicApply a labeled Bt or spinosad· every 1 wk · ~3 wksmoderate evidence — extension confidence
If damage continues, apply a labeled Bacillus thuringiensis (kurstaki) or spinosad product per the label, targeting small larvae; Bt works best on young first- and second-instar cutworms.
Phosphorus deficiency
DeficiencymoderateUnusual this time of year.
- CulturalCheck soil test and soil temperaturestrong evidence — extension confidence
Purpling in cold spring soils is often temporary, since cold roots can't take up phosphorus that's actually present; warm weather usually resolves it, so confirm a true shortage with a soil test before adding phosphorus.
- OrganicAdd phosphorus only if the test calls for itmoderate evidence — extension confidence
If low phosphorus is confirmed, work a phosphorus source into the root zone per the test recommendation, and keep soil pH in range since extreme pH ties up phosphorus.
Aphids
Pestlow- CulturalBlast off with water· every 3 days · ~2 wksstrong evidence — extension confidence
Knock colonies off with a strong jet of water in the morning; repeat every few days. Light infestations rarely need more.
- OrganicInsecticidal soap - label use only· every 1 wk · ~3 wksmoderate evidence — extension confidence
For persistent colonies apply insecticidal soap to undersides per label. Avoid open flowers.
Edema (oedema)
Disorderlow- CulturalBalance watering and humiditystrong evidence — extension confidence
Edema comes from the plant taking up more water than it releases, not a pathogen, so water less often and water in the morning so roots aren't taking up water faster than leaves transpire on cool, humid days.
- CulturalImprove airflow and drainagestrong evidence — extension confidence
Space plants for good air movement, improve soil and container drainage, and avoid overcrowding under cover; affected leaves won't recover but new growth comes in normally once conditions balance.
Magnesium deficiency
Deficiencylow- CulturalConfirm with a soil test, then correct· every 2 wks · ~4 wksmoderate evidence — extension confidence
Interveinal yellowing on older leaves suggests magnesium. Confirm with a test; if low, a dilute Epsom-salt foliar spray is a short-term fix while you amend the soil.
Nitrogen deficiency
Deficiencylow- CulturalFeed with balanced fertilizer· every 2 wks · ~4 wksstrong evidence — extension confidence
Apply a balanced organic fertilizer or fish emulsion; new growth greens up within ~2 weeks. Don't overcorrect.
Sunscald
Disorderlow- CulturalKeep canopy coverstrong evidence — extension confidence
Stop over-pruning and let foliage shade the fruit; shade cloth helps in heat waves. Damaged fruit is still edible if you cut out the patch.
Transplant shock
DisorderlowUnusual this time of year.
- CulturalWater in well and provide shade· every 1 days · ~1 wksstrong evidence — extension confidence
Water transplants in thoroughly at planting and keep the root zone evenly moist for the first week or two, and provide temporary shade during hot, sunny, or windy spells to reduce stress while roots establish.
- CulturalHarden off and plant gently next timestrong evidence — extension confidence
Most plants recover on their own; to prevent recurrence, harden off seedlings before planting, set them out in mild weather or evening, and avoid disturbing the roots when transplanting.