Local planting guide · Southwest
zip 85037
Phoenix is in USDA hardiness zone 9b, with average winter lows of 25°F to 30°F. The local growing season runs roughly 01/05 through 01/03 (~365 days). This zip falls within the Southwest growing region.
- USDA zone
- 9b 25°F to 30°F
- Last spring frost
- 01/05
- First fall frost
- 01/03
- Growing season
- 365 days
- Compatible crops
- 37
- Growing region
- Southwest
Right now in Phoenix
Week 18 priorities
On the docket: transplant out after last frost · direct sow after last frost. See the full calendar →
Gardening in Phoenix
Phoenix's gardening calendar runs counter to most of the country. With a 365-day growing season and frost risk concentrated around early January, gardeners here operate in a year-round mindset that inverts the spring-dominated rhythm of temperate zones. Temperatures rarely drop below 25 to 30°F in zone 9b, but summer heat is the defining challenge: Phoenix regularly exceeds 110°F from June through September. This creates a bimodal planting strategy. Cool-season crops (tomatoes, peppers, leafy greens) thrive in fall and winter, making October through March the primary garden season. Heat-tolerant perennials like figs, pomegranates, jujubes, and goji berries flourish without winter chill concerns because they evolved in similarly arid climates. The low winter chilling hours (typically 150 to 200 hours below 45°F annually) make standard deciduous fruit varieties unreliable, but low-chill cultivars specifically bred for deserts and southern regions fill that gap. Water availability and alkaline soil (common in Sonoran Desert soils) shape variety selection and soil amendment strategy.
Regional context · Southwest
What the Southwest brings to Phoenix
Hot, arid, irrigated. Two growing seasons in the low desert: cool October to April, hot May to September. Date palms and citrus thrive at low elevation; apples and stone fruit at higher elevations. The chile-pepper belt of the country.
Common challenges
Issues that most often defeat home gardeners in zone 9b, drawn from the broader USDA zone profile.
- ▸ Heat stress in summer
- ▸ Insufficient chill for most apples
- ▸ Salt spray near coasts
What defeats new gardeners in Phoenix
Phoenix gardeners face three recurring headwinds. First, alkaline soil and high salts accumulate in desert irrigation water, raising pH to 7.5 to 8.5 and preventing nutrient uptake in acid-loving plants like blueberries or citrus on susceptible rootstocks. Second, monsoon-driven humidity from July through September invites fungal diseases (powdery mildew, root rot) that desert-adapted plants evolved to avoid, especially in newly established landscapes with poor air circulation. Third, late-winter frost damage strikes unexpectedly around January 3 to 5 when new growth emerges after warm December days. Tender perennials like pomegranates or young fig trees that break dormancy early can lose new growth to the frost window, reducing fruiting or causing structural dieback. Summer sunscald on thin-barked trees and heat stress on recently transplanted plants round out the seasonal hazard list.
Crops that grow in Phoenix
37 crops from our catalog match zone 9b, grouped by type.
Tree fruit
11 crops
zone 9b Fig
Ficus carica
zones 7a–10b
zone 9b Asian Persimmon
Diospyros kaki
zones 7a–10a
zone 9b Pomegranate
Punica granatum
zones 7b–10a
zone 9b Jujube
Ziziphus jujuba
zones 6a–9b
zone 9b Lemon
Citrus limon
zones 9a–11b
zone 9b Orange
Citrus sinensis
zones 9a–11b
zone 9b Lime
Citrus aurantiifolia
zones 9b–11b
zone 9b Grapefruit
Citrus paradisi
zones 9a–11b
Berries
2 crops
Vegetables
18 crops
zone 9b Tomato
Solanum lycopersicum
zones 3a–10b
zone 9b Sweet Pepper
Capsicum annuum
zones 4a–10b
zone 9b Hot Pepper
Capsicum species
zones 4a–10b
zone 9b Eggplant
Solanum melongena
zones 5a–10b
zone 9b Cabbage
Brassica oleracea var. capitata
zones 3a–9b
zone 9b Kale
Brassica oleracea var. acephala
zones 3a–9b
zone 9b Collards
Brassica oleracea var. acephala
zones 4a–9b
zone 9b Cucumber
Cucumis sativus
zones 3b–10a
Herbs
6 crops
Plan the year
Planting calendar for Phoenix
Year-view of seed starting, transplanting, planting, pruning, fertilizing, harvest, and pest-watch windows tuned to Phoenix's local frost dates.
Week ? · loading
This week in Phoenix, AZ (zone 9b)
Quiet week in Phoenix, AZ (zone 9b). this week is a good time to step back and plan ahead.
Nothing critical on the calendar this week.
187 bars · 37 crops
Calendar logic combines NOAA frost normals with crop-specific timing data. Local microclimate and weather always overrules the calendar; use this as a starting point.
Top pests for zone 9b
Ranked by how many crops in your zone they affect. Click through for IPM controls and signs to watch for.
Multiple species (Aphididae)
Small soft-bodied sap-sucking insects that reproduce explosively in spring. Excrete honeydew that supports sooty mold and attracts ants. Transmit viral diseases.
Multiple species (Aleyrodidae)
Tiny white moth-like flying insects that feed on plant sap and excrete honeydew. Transmit numerous viral diseases including tomato yellow leaf curl virus.
Meloidogyne species
Microscopic soil-dwelling worm that forms galls on roots, reducing vigor and yield.
Tetranychus urticae
Tiny mite that feeds on leaf undersides, causing stippling and webbing during hot dry weather.
Multiple species (Chrysomelidae)
Tiny black or bronze jumping beetles that put hundreds of small holes in seedling leaves. Most damaging on direct-seeded brassicas and young eggplant.
Odocoileus species
Whitetail and mule deer browse can devastate orchards and gardens, particularly in winter when food is scarce. Antler rub on young trunks kills saplings outright.
Pseudococcidae spp.
Soft white waxy insects that cluster at leaf joints, fruit stems, and root crowns. Honeydew secretion supports sooty mold; root mealybugs cause decline that mimics drought.
Coccoidea spp.
Sap-sucking insects that attach to bark, leaves, and fruit, secreting honeydew that fuels sooty mold. Heavy infestations weaken trees and cause leaf yellowing.
Top diseases for zone 9b
Ranked by how many crops in your zone they affect. Click through for symptoms, controls, and resistant varieties.
Pseudoperonospora cubensis (cucurbits) and others
Water mold (oomycete, not a true fungus) that thrives in cool damp conditions. Spreads rapidly through cucurbit and brassica plantings on wind-borne spores.
Cucumber mosaic virus, Tobacco mosaic virus, and others
Family of plant viruses producing mottled yellow-and-green leaf patterns. Vectored primarily by aphids; some are seed-transmitted or spread by handling tools and tobacco products.
Pythium and Rhizoctonia species
Soil-borne complex of water molds and fungi that kill seedlings before or shortly after emergence. The single most common cause of seed-starting failures.
Fusarium oxysporum
Soil-borne fungal disease that plugs vascular tissue and kills affected plants. Persists in soil for many years; impossible to eliminate once established.
Sclerotium rolfsii
Soil-borne fungal disease most damaging in warm humid Southern conditions. White mycelial fans and small mustard-seed-sized sclerotia at the soil line are diagnostic.
Calcium deficiency physiological disorder
Not a true disease but a calcium-uptake disorder caused by inconsistent soil moisture during fruit development. The dominant cause of damaged first-fruit on home tomato plantings.
Capnodium spp.
Black fungal coating that grows on honeydew secreted by aphids, scale, mealybugs, and whiteflies. Doesn't infect plant tissue directly but blocks photosynthesis and disfigures fruit.
Tomato spotted wilt orthotospovirus (TSWV)
Virus vectored by thrips, particularly western flower thrips. Wide host range and growing global distribution. No cure once infected.
Companion planting suggestions
Beneficial pairings drawn from companion data, filtered to crops that grow in zone 9b.
- Fig + Rosemary
Rosemary tolerates the dry sites figs prefer and provides aromatic pest deterrence.
- Tomato + Basil
The classic Italian pairing. Basil's volatile oils are reported to repel hornworms and whiteflies, and the two crops share the same warm-season schedule and water needs. Plant basil between tomato cages.
- Sweet Pepper + Basil
Same warm-season culture, same watering schedule. Basil reportedly improves pepper flavor and repels aphids and thrips that are pepper's primary pests.
- Hot Pepper + Basil
Compatible heat-loving culture, similar water needs. Basil interplanted between hot pepper plants supports beneficial insects and reduces aphid pressure.
- Lettuce + Tomato
Lettuce planted at tomato's base benefits from afternoon shade as the tomato grows, extending the lettuce harvest into early summer. Different root depths avoid competition.
- Cabbage + Onion
Onion smell confuses cabbage moth. Both prefer similar moisture and fertility. The onion-cabbage interplanting is a Northern European tradition.
Soil types reference
Soil texture and pH decide what grows easily on your specific lot. Find the closest match below for crop recommendations and amendment guidance.
Practical tips for Phoenix
Select low-chill fruit varieties explicitly bred for desert climates. Standard 'Honeycrisp' apple requires 400-plus chill hours and fails in Phoenix; 'Anna' apple, 'Babcock' peach, and 'Tropic Snow' mango thrive with Phoenix's 150 to 200 winter chill hours. Second, time warm-season crops to finish before June heat peaks. Plant tomato and pepper transplants by late February so they're established and fruiting before July temperatures stress pollination and set; replant in late August for fall harvest. Third, amend alkaline soil with sulfur at planting time (aim for pH 6.5 to 7.0 for most crops) and mulch heavily with compost to moderate soil temperature swings and reduce water loss in the intense desert sun. Coffee grounds or sulfur-treated compost acidify faster than raw compost alone.
Frequently asked questions
- What's the best time to plant tomatoes in Phoenix?
Plant tomato transplants in late February through March for spring harvest before June heat reduces pollination and fruit set. A second planting window opens in late August for fall harvest in November and December when temperatures cool below 95°F. Avoid transplanting in April through July.
- Which fruit trees actually work in Phoenix's low-chill winters?
'Anna' and 'Dorset Golden' apples, 'Tropic Snow' mango, 'Babcock' and 'Tropic Sweet' peaches, and 'Fuerte' avocado all fruit reliably on Phoenix's 150 to 200 winter chill hours. Figs, pomegranates, jujubes, and goji berries need virtually no winter chill and excel in zone 9b's heat and drought.
- How do I protect frost-tender plants from the January frost window?
The January 3 to 5 frost event catches early-breaking plants unguarded. Delay heavy pruning or fertilizing until late January to suppress premature growth. Apply frost cloth or shade cloth to young growth in early January if warm December weather triggered budbreak. Pomegranates and young figs respond well to row cover protection.
- What's the main soil issue in Phoenix, and how do I fix it?
Phoenix's alkaline soil and high salt content from irrigation water raise pH to 7.5 to 8.5, locking up iron, manganese, and zinc. Incorporate sulfur at planting time (1 to 2 pounds per 100 square feet) to lower pH toward 6.5. Mulch heavily with compost and avoid repeated shallow watering that deposits salts on the surface.
- How do I keep plants alive through Phoenix's 115°F summers?
Mulch generously (3 to 4 inches of wood chips or compost) to keep soil temperature 10 to 15°F cooler. Provide afternoon shade for recently established plants and heat-sensitive crops like lettuce or young citrus. Increase irrigation frequency in sandy desert soils; shallow, frequent watering beats infrequent deep soaking in intense heat.
- Should I amend the desert soil before planting?
Yes. Desert soils are low in organic matter and often compacted. Work in 2 to 4 inches of compost before planting and incorporate sulfur to moderate pH. Compost improves water retention in sandy soils and feeds slow-growing plants. Reapply mulch annually as it breaks down.
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Frost data: NOAA Climate Normals 1991-2020, station USW00023183. Local microclimates can shift these dates by a week or more.
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