Local planting guide · Southwest
zip 85285
Tempe is in USDA hardiness zone 10a, with average winter lows of 30°F to 35°F. The local growing season runs roughly 01/05 through 01/03 (~365 days). This zip falls within the Southwest growing region.
- USDA zone
- 10a 30°F to 35°F
- Last spring frost
- 01/05
- First fall frost
- 01/03
- Growing season
- 365 days
- Compatible crops
- 28
- 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's growing season is essentially year-round, with only a brief frost window in early January when minimum temperatures dip to 30-35°F. This inverts the typical gardening calendar familiar to northern zones. Winter and spring (October through May) is the prime growing season for vegetables and tender fruits. Summer is characterized by extreme heat; Tempe regularly exceeds 110°F from June through September, which limits cool-season crops to shade-protected areas or sheltered microclimates. The dominant constraint is not frost protection but rather managing the desert heat and water needs. Crops that thrive include heat-loving vegetables (tomatoes, peppers, eggplant), Mediterranean fruits (figs, pomegranates), and cool-season crops grown during the cooler months. Winter in Tempe is mild and frost-free, allowing a full cycle of leafy greens, brassicas, and root crops from October through March without frost protection. Soil tends toward alkalinity, typical of desert regions, and benefits from sulfur amendment and compost to improve structure and nutrient availability.
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 10a, drawn from the broader USDA zone profile.
- ▸ No chilling for traditional temperate fruit
- ▸ Hurricane exposure
- ▸ Heat-tolerant cultivars only
What defeats new gardeners in Tempe
The transition into summer heat is the steepest challenge. Spring plantings of lettuce, spinach, and brassicas bolt or wilt in May as temperatures climb; timing the harvest window requires succession planting in February and March with no reprieve until September. Summer soil temperatures exceed plant stress thresholds, and shallow watering becomes ineffective as evaporation rates soar. Water supply is the second binding constraint. Desert irrigation patterns and summer scarcity mean that unirrigated plots fail within weeks. Monsoon rains (July through September) arrive as intense, brief storms after prolonged drought; drainage becomes critical to prevent root rot in heavy clay soils. Third, alkaline soil pH is endemic; most vegetables prefer pH 6.0-7.0, while Tempe soils often range 7.5-8.5. Neglecting soil amendment reduces nutrient availability and increases deficiency symptoms, particularly iron chlorosis visible as yellowing new growth.
Crops that grow in Tempe
28 crops from our catalog match zone 10a, grouped by type.
Tree fruit
12 crops
zone 10a Fig
Ficus carica
zones 7a–10b
zone 10a Asian Persimmon
Diospyros kaki
zones 7a–10a
zone 10a Pomegranate
Punica granatum
zones 7b–10a
zone 10a Lemon
Citrus limon
zones 9a–11b
zone 10a Orange
Citrus sinensis
zones 9a–11b
zone 10a Lime
Citrus aurantiifolia
zones 9b–11b
zone 10a Grapefruit
Citrus paradisi
zones 9a–11b
zone 10a Avocado
Persea americana
zones 9b–11b
Berries
3 crops
Nuts
1 crop
Vegetables
10 crops
zone 10a Tomato
Solanum lycopersicum
zones 3a–10b
zone 10a Sweet Pepper
Capsicum annuum
zones 4a–10b
zone 10a Hot Pepper
Capsicum species
zones 4a–10b
zone 10a Eggplant
Solanum melongena
zones 5a–10b
zone 10a Cucumber
Cucumis sativus
zones 3b–10a
zone 10a Summer Squash
Cucurbita pepo
zones 3b–10a
zone 10a Melon
Cucumis melo
zones 5a–10a
zone 10a Watermelon
Citrullus lanatus
zones 5b–10a
Herbs
2 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 10a)
Quiet week in Tempe, AZ (zone 10a). this week is a good time to step back and plan ahead.
Nothing critical on the calendar this week.
147 bars · 28 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 10a
Ranked by how many crops in your zone they affect. Click through for IPM controls and signs to watch for.
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.
Meloidogyne species
Microscopic soil-dwelling worm that forms galls on roots, reducing vigor and yield.
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.
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.
Tetranychus urticae
Tiny mite that feeds on leaf undersides, causing stippling and webbing during hot dry weather.
Ceratitis capitata
Quarantine pest in many regions. Adult females puncture ripening fruit to lay eggs; larvae tunnel through the flesh, causing premature drop and rot.
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.
Top diseases for zone 10a
Ranked by how many crops in your zone they affect. Click through for symptoms, controls, and resistant varieties.
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.
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.
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.
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.
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.
Colletotrichum gloeosporioides
Most damaging mango disease worldwide. Fungal spores infect blossoms and developing fruit during humid weather, producing black sunken lesions that expand on ripening fruit.
Multiple species (Erysiphales)
Surface-feeding fungal disease producing white powdery growth on leaves and stems. Reduces yield by stealing photosynthate and accelerating senescence.
Companion planting suggestions
Beneficial pairings drawn from companion data, filtered to crops that grow in zone 10a.
- 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.
- Okra + Hot Pepper
Both heat-loving warm-season crops with similar water and fertility needs. Hot pepper at okra's base benefits from the slight afternoon shade in extreme summer heat.
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
Shift your seasonal thinking to the cooler windows. Plant heat-loving crops (tomatoes, peppers, eggplant) in late February through March for a spring harvest before June heat, then delay fall plantings to late August so plants establish through the cooler September-October period. Use 30-50% shade cloth from May through September to extend the season for salad greens and reduce heat stress on perennial crops. Install drip irrigation on a timer; hand-watering in summer heat cannot keep pace with evaporation rates and wastes time and water. Water deeply and less frequently to encourage deep root systems that tolerate heat stress better than shallow, daily sprinkling.
Frequently asked questions
- What vegetables grow best in Tempe?
Winter and spring vegetables (October-March) thrive: tomatoes, peppers, eggplant, squash, leafy greens, root crops, and brassicas. Summer is challenging for cool-season crops but heat-loving varieties managed with shade cloth can succeed. Fall plantings (August-October) capture the long autumn and mild winter.
- When should I plant tomatoes in Tempe?
Plant transplants in late February or early March to harvest before June heat. For fall tomatoes, start seeds in June and transplant in August to mature during the cooler, longer days of September-November. This gives two distinct tomato seasons.
- How do I protect my garden from summer heat?
Shade cloth (30-50% density) is essential from May through September. Mulch heavily to cool soil and reduce evaporation. Drip irrigation on a timer is non-negotiable; hand-watering cannot compete with evaporation. Choose heat-tolerant varieties and time plantings to avoid maturity during peak June-August heat.
- Is frost a risk in Tempe?
Frost risk is minimal and brief. Last spring frost occurs around January 5, and first fall frost around January 3, creating only a narrow frost window in early January. Most years see frost for just a few nights in that window, leaving 360+ frost-free days.
- What's the biggest challenge for Tempe gardeners?
Summer heat and water scarcity. Extreme temperatures (110°F+) kill cool-season crops and stress warm-season varieties. Reliable irrigation is non-negotiable in the desert. Successful gardening requires either inverting your season to focus on winter or implementing intensive summer management.
- How do I amend Tempe's alkaline soil?
Desert soils typically range pH 7.5-8.5 and lack organic matter. Apply sulfur to lower pH gradually and amend with 2-3 inches of compost annually to improve structure and water retention. Iron deficiency symptoms (yellowing new leaves) respond to chelated iron or additional sulfur.
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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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