Zone 10b planting calendar

What to plant in September: zone 10b

A rule-of-thumb starting point for zone 10b: last spring frost around January 15, first fall frost around December 30. Zones are set by winter lows, not frost dates, so two gardens in the same zone can be weeks apart. Measure your ZIP below for dates from your area's own 30-year record.

These are zone-average dates. Check an area-level frost estimate from thirty years of nearby weather history and this calendar retimes itself.
Typical last frost: January 15
Typical first frost: December 30
Winter lows: 35 to 40 °F
Zone 10b Almanac. What growers here actually recorded: sowing weeks, days to first pick, and yields.

Plan & order

  • Inventory and order seed2 sowings: Sep 25 and Sep 1

    Sort what you already have, toss anything over 3 years old, and order early while varieties are in stock. Sowing again a few weeks later keeps the harvest coming instead of arriving all at once.

Start indoors for fall

  • Broccoliaround Sep 4

    Fall broccoli window opens. Sow trays any time in the next four weeks.

  • Kalearound Sep 21

    Fall kale window opens. Sow trays any time in the next four weeks.

Direct sow for fall

  • Parsleyaround Sep 23

    Fall parsley window opens. Sowing now beats the last-minute date by a month of growth.

  • Bush beanaround Sep 28

    Fall bush bean window opens. Sowing now beats the last-minute date by a month of growth.

  • Lettucearound Sep 29

    Succession sowing 3 of 3. Sow every 21 days for a steady cut.

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