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Arizona · Local Gardening
Frost dates, planting zones, soil types, and what actually thrives in Arizona — from mountains to coast.
Frost dates & zones
Arizona spans USDA zones 5a (Flagstaff highlands / 7,000 ft) to 10b (Yuma / Sonoran Desert). Verify your exact zone and frost dates with your county Extension office — elevation and microclimates create real variation.
Hardiness Zones
5a (Flagstaff highlands / 7,000 ft) to 10b (Yuma / Sonoran Desert)
Last frost: varies by region. First frost: varies by region.
Look up your exact zone by ZIP at USDA →What grows well here
Arizona caliche must be broken through or worked around — it blocks drainage and kills plants. Add sulfur to lower alkaline pH. Organic matter disappears fast in desert heat — add compost heavily and mulch aggressively. UA Extension county offices are essential for desert-specific guidance.
Know your soil
Arizona desert soils are typically alkaline, low in organic matter, and high in caliche (calcium carbonate hardpan). The Phoenix metro has rocky, clay-heavy soils with caliche layers that block drainage and root growth. The Flagstaff highlands have more acidic forest soils. The Salt and Verde river valleys have somewhat better alluvial soils.
Map your soil type with USDA Web Soil Survey →Free soil testing
Free or low-cost soil testing available through your county Extension office
Results include specific lime and fertilizer recommendations
Most states offer testing April through fall — fees apply in winter
Results typically returned within 10 business days
Next steps
Preserve what you grow
Arizona Extension offers food preservation workshops — and NWS has the full canning guides.
Food IndependenceGet the checklist
Spring prep, frost protection, soil test timing, and compost setup — timed to regional frost dates.
AZ Checklists