Local planting guide · Southwest
zip 85046
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 growing season is defined by extremes of heat rather than cold. With winter low temperatures between 25 and 30°F, zone 9b presents almost no risk of freezing damage most of the year, creating a nearly 365-day frost-free window that is exceptional among North American gardening zones. However, heat drives planting decisions far more than frost does. Summer temperatures routinely exceed 110°F from June through August, which restricts the viability of most vegetables and tender crops to narrow windows in fall and early spring. Many gardeners new to Phoenix expect the same spring-plant, fall-harvest rhythm as cooler zones, only to watch tender crops wilt in March heat before reaching productivity. Successful gardeners instead adopt a winter-primary schedule and exploit the long shoulder seasons for tomatoes, peppers, and leafy greens. Tree fruits like figs, persimmons, pomegranates, and jujubes thrive with the intense heat and abundant sunshine but demand careful summer irrigation to sustain fruit development. Goji berries, adapted to arid regions, perform exceptionally well. The key constraint is not dormancy or freeze protection, but water availability and crop scheduling to avoid peak summer heat stress.
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
The desert heat that makes Phoenix gardening distinct creates three primary obstacles. First, late spring frost damage in March and April can devastate tomatoes, peppers, or stone fruit in bloom, despite the zone's reputation for mildness. Gardeners often plant too early, seduced by the mild winter, only to lose the crop to a late frost. Second, summer heat so extreme that most common vegetables cannot photosynthesize or set fruit during June, July, and August. Tomatoes and peppers often require 30 to 50% shade cloth to prevent fruit scald and blossom-end rot. Third, alkaline, caliche-laden soil common in the Phoenix area requires either breaking through caliche layers or building raised beds with imported soil. Many Phoenix gardens fail not from cold or pests, but from shallow, impervious soil and underestimation of irrigation demands during the hot season.
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
Plant tomatoes and peppers in late August and early September for a fall-winter harvest, not in spring. This window avoids the March-April frost risk and allows the crop to mature during mild, long-day fall months before the growing season slows in late autumn. Second, use 30 to 50% shade cloth from June through August for heat-sensitive fruits like stone fruits and young citrus; the reduction in scorching far outweighs the modest loss of photosynthetically active radiation during the hottest months. Third, water deeply and infrequently rather than daily and shallow. The desert's low humidity and intense sun evaporate shallow moisture before roots can access it; weekly deep watering to 12 inches or more encourages deep rooting and resilience to heat stress.
Frequently asked questions
- What are the easiest fruit trees to grow in Phoenix?
Figs, persimmons, jujubes, and pomegranates are nearly foolproof in zone 9b. All tolerate the heat, require minimal winter chill, and produce reliably with basic irrigation. Citrus also thrives, though tender varieties benefit from frost protection during rare hard-freeze events.
- When should I plant tomatoes in Phoenix?
Plant in late August through early September for fall and winter production. A March or April frost can still damage spring plantings before harvest, making spring planting risky. Fall plantings mature through the mild winter and bypass summer heat entirely.
- What's the biggest weather threat to a Phoenix garden?
Late spring frost in March or April, despite the zone's reputation for mildness. An unexpected freeze at bloom time can wipe out stone fruit or tender crops planted too early in spring. Wait until late April to plant frost-sensitive crops safely.
- Do I need to worry about hard freezes in Phoenix?
Hard freezes below 25°F are rare in zone 9b, occurring only a few times per decade. However, they do happen occasionally. Tender perennials and young citrus benefit from frost cloth protection or placement against south-facing walls during winter.
- Can I grow tomatoes and peppers year-round in Phoenix?
Not reliably. Summer heat exceeding 110°F causes blossom drop and fruit scald, making June through August nearly impossible for productive growth. Winter and shoulder seasons from September through May are far more productive for these crops.
- What soil amendments do Phoenix gardeners need most?
Organic matter to improve water retention and drainage, and sulfur or compost to acidify the often-alkaline desert soil. Many Phoenix gardens sit on caliche, a calcium carbonate layer that blocks drainage and roots; breaking or removing it is essential for deep rooting.
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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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