Fall · September 8, 2026

Phoenix, Arizona

Deserts & Dry Basins

Now

42°C · Clear

Today

42° / 31°

Soil 6 cm

37°C

First frost

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Gardening in Phoenix

AI field guide · refreshed weekly

Phoenix Gardening: Early Fall Planting Season Begins

Zone 10a with 109 days until the first average frost (late December). Soil at 38°C (100°F) is still hot but cooling—ideal for germinating cool-season crops that need warmth to sprout but will mature in mild winter temps. Your 219 frost-free days since spring mean you're entering the prime planting window for fall vegetables.

Sow outdoors now

  • Lettuce & leafy greens

    Sow leaf lettuce, romaine, spinach, and arugula directly now; they germinate at 38°C and will be harvestable in 6–8 weeks before frost.

  • Radishes

    Direct-sow varieties like 'Cherry Belle' or 'French Breakfast'; ready in 25–30 days in cooling soil.

  • Peas (snap & snow)

    Sow 'Sugar Snap' or 'Oregon Sugar Pod' now; they'll climb through winter and produce Feb–March in your zone.

  • Carrots

    Direct-sow 'Nantes' or 'Chantenay' types; germination is slow at 38°C but will accelerate as soil cools this week.

  • Brassicas (broccoli, cabbage, cauliflower)

    Sow seeds of 'Calabrese' broccoli or 'Stonehead' cabbage directly for transplanting or direct harvest in 60–90 days.

Start indoors now

  • Tomatoes (winter varieties)

    Start 'Phoenix' or 'Surefire' indoors now for transplanting in 4–6 weeks; they'll set fruit in mild January–February.

  • Peppers (long-season)

    Start 'NadaPeño' or sweet bell peppers indoors; they need 8–10 weeks to transplant size and will produce through spring.

  • Eggplant

    Start 'Orient Express' or 'Ichiban' indoors for transplanting in 6 weeks; they thrive in Phoenix's mild winter.

Harvest now

  • Summer squash (end of season)

    Pick any remaining zucchini or yellow squash before plants decline in heat; pull plants after final harvest.

  • Basil & herbs

    Harvest heavily before frost; basil will decline as temps drop below 15°C (59°F) in December.

  • Melons & cucumbers

    Collect ripe fruit now; vines will slow as soil cools and daylight shortens.

Tasks this week

  • Amend beds with 5 cm (2 in) of compost before sowing; Phoenix soil is often alkaline and low in organic matter.
  • Water newly sown seeds daily until germination; soil will cool from 38°C to ~32°C (90°F) by week's end, slowing evaporation.
  • Set up drip irrigation or soaker hoses for fall crops; wind gusts to 30 km/h (19 mph) by Friday will dry soil fast.
  • Remove spent summer plants and clear debris to reduce pest habitat heading into winter.
  • Scout for spider mites and whiteflies, which thrive in heat and low humidity (24% today)—spray with neem oil if needed.

Watch out for

  • Soil still too hot for many seeds: wait until next week if germination fails; 38°C can cook some seedlings.
  • Monsoon moisture (7.9 mm forecast Sept 12) may arrive suddenly—ensure drainage is clear to prevent root rot.
  • Intense UV and wind: use 30% shade cloth for newly sown beds and transplants until established.

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