Local planting guide · Southwest
zip 85280
Tempe 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 Tempe
Week 18 priorities
On the docket: transplant out after last frost · direct sow after last frost. See the full calendar →
Gardening in Tempe
Tempe gardening operates on an inverted calendar compared to most of the country. The region's defining feature is not the threat of cold but the intensity of summer heat, with daytime temperatures regularly exceeding 105°F from June through August. With a last spring frost date of January 5 and an extended growing season of 365 days, Tempe experiences essentially year-round planting potential. The practical gardening calendar divides into two seasons: a long, mild winter window from October through May when cool-season crops and tender perennials thrive, and a compressed spring interval for summer crops that must set fruit before peak heat arrives in June.
The crops that flourish in Tempe reflect adaptation to heat and dryness rather than cold tolerance. Figs, Asian persimmons, pomegranates, jujubes, and goji berries are ideally suited because they tolerate intense dry heat and require minimal water once established. Tomatoes and peppers are equally productive when planted by late February, early enough to set fruit during the mild spring before nighttime temperatures consistently exceed 75°F. Success in Tempe hinges not on managing frost risk but on timing plantings to avoid the peak heat window and selecting varieties bred for southwestern conditions.
Regional context · Southwest
What the Southwest brings to Tempe
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 Tempe
Summer heat stress defeats more Tempe gardeners than any single other factor. Tomatoes, peppers, and most vegetable crops stop setting fruit when nighttime temperatures exceed 75°F, a threshold reached reliably by late May and sustained through August. The result is a mid-summer productivity gap when plants survive but produce nothing.
Water management and soil chemistry compound the challenge. Tempe's sandy desert soils are often alkaline, drain rapidly, and hold nutrients poorly. Without consistent drip irrigation and frequent organic amendments, plants stress quickly during the hot season. Afternoon sun also damages fruit directly; sunscald on peppers and tomatoes occurs when exposed to intense afternoon heat during peak summer.
Crops that grow in Tempe
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 Tempe
Year-view of seed starting, transplanting, planting, pruning, fertilizing, harvest, and pest-watch windows tuned to Tempe's local frost dates.
Week ? · loading
This week in Tempe, AZ (zone 9b)
Quiet week in Tempe, 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 Tempe
Plant tomatoes and peppers by late February to ensure fruit set during the mild spring before heat peaks in May. Heat-bred varieties like 'Phoenix' and 'Heatwave II' outperform traditional cultivars significantly in Tempe's climate.
Use 30-50% shade cloth from May through September for any crop sensitive to direct sun. East-facing placement with afternoon shade allows morning sun for growth while blocking the intense afternoon heat spike.
Treat October through April as the premium growing season. Succession-plant cool-season crops (brassicas, leafy greens, root crops) in September, October, and November to maintain continuous harvest through winter. This inverted thinking runs counter to gardeners from cooler regions but is essential for Tempe productivity.
Frequently asked questions
- What are the best crops for year-round gardening in Tempe?
Figs, persimmons, pomegranates, and jujubes thrive in heat and require minimal water once established. Tomatoes and peppers are highly productive when planted by late February. Winter crops including lettuce, broccoli, and spinach flourish from October through April. Success depends on matching planting time to each crop's heat or cold tolerance.
- When should I plant tomatoes in Tempe?
Late February through early March is ideal. This timing allows fruit set during mild spring before nighttime temperatures exceed 75°F in May, which shuts down flowering in most varieties. Heat-tolerant cultivars like 'Phoenix' and 'Heatwave II' perform best.
- What is the biggest weather risk for gardening in Tempe?
Summer heat stress, not frost, is the dominant constraint. Temperatures exceed 105°F from June through August, stopping fruit set in tomatoes, peppers, and many other crops. Water availability and maintaining irrigation in sandy desert soils ranks second.
- How do I protect vegetables during Tempe's summer heat?
Use 30-50% shade cloth from May through September and maintain consistent soil moisture with drip irrigation. Consider shifting productivity focus to October through April when temperatures are mild and cool-season crops flourish.
- Is frost a concern for Tempe gardeners?
Frost is not a practical constraint. With a last spring frost date of January 5 and a 365-day growing season, Tempe experiences essentially year-round growing potential. Heat timing, not frost timing, governs the planting calendar.
- What soil amendments do Tempe gardens need?
Desert soils are sandy, often alkaline, and low in organic matter. Incorporate 2-3 inches of compost annually, use mulch to slow evaporation, and consider sulfur if soil pH exceeds 7.5. Consistent amendments are essential for vegetable productivity.
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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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