Calendula in Zone 10a & 10b
Calendula officinalis
Yes, calendula grows in zones 10a and 10b. Start seeds indoors in Aug–Sep and plant out in Sep–Nov. For a fall crop, start seeds indoors in Aug–Sep and plant out in Sep–Nov.
When to plant calendula in zone 10b
Zones 10a and 10b share the same average frost dates, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. In your zone it needs a head start on the heat that direct-sowing elsewhere doesn't require.
| Window | Fall window |
|---|---|
| Start indoors | Aug–Sep |
| Direct sow / transplant outside | Sep–Nov |
| Estimated bloom | ~50 days after transplanting |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Zone 10b dates sourced from growinginthegarden.com.
Fall window: the last sowing date is the average first frost minus days to maturity, the method in Purdue Extension's fall garden guide, which lists calendula for late-summer planting.
Plant alongside it in zone 10b
These go outside within two weeks of calendula in zone 10b, so one planting day can cover them.
- Bachelor's Button (Cornflower)Sep–Nov
- DelphiniumSep–Nov
- Gaillardia (Blanket Flower)Sep–Nov
- LarkspurSep–Jan
- PetuniaSep–Mar
- SnapdragonSep–Feb
Calendula is one of the earliest things you can get in the ground. It tolerates a light frost and is often started before most of the garden is even planted, and it earns its keep once established, commonly reported to draw in the predatory insects that prey on tomato hornworms. What you get for the trouble is a low, 12- to 18-inch mound covered in simple daisy-like blooms in orange or yellow.
How calendula fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Calendula needs about 50 days from sowing to first bloom.
Calendula planting windows in every zone
Zone 10b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 2a & 2b | Apr 1–Apr 8 | May 6–May 13 | Jun 25–Jul 2 |
| 3a & 3b | Apr 11–Apr 18 | May 16–May 23 | Jul 5–Jul 12 |
| 4a & 4b | Mar 27–Apr 3 | May 1–May 8 | Jun 20–Jun 27 |
| 5a & 5b | Mar 22–Mar 29 | Apr 26–May 3 | Jun 15–Jun 22 |
| 6a & 6b | Mar 7–Mar 14 | Apr 11–Apr 18 | May 31–Jun 7 |
| 7a & 7b | Feb 20–Feb 27 | Mar 27–Apr 3 | May 16–May 23 |
| 8a & 8b | Feb 4–Feb 11 | Mar 11–Mar 18 | Apr 30–May 7 |
| 9a & 9b | Dec 28–Jan 4 | Feb 1–Feb 8 | Mar 23–Mar 30 |
| 10a & 10bFall window (your zone) | Aug–Sep | Sep–Nov | ~50 days after transplanting |
| 11a & 11b | Nov 13–Nov 20 | Dec 18–Dec 25 | Feb 6–Feb 13 |
Bloom dates are about 50 days after the sow or plant-out date, not after starting seeds indoors.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
Good companions
- Tomato: Penn State Extension confirms calendula attracts beneficial insects that prey on aphids: the more specific claim that it targets hornworm predators isn't what that research shows, so treat calendula as a general aphid-predator draw near tomatoes rather than a hornworm-specific one.
Where to buy calendula seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's calendula seeds)
Varieties we recommend, and where to get them:
- 'Pacific Beauty': Utah State University Extension notes this variety, along with 'Coronet', has increased heat tolerance compared to other calendula, useful if your garden runs warmer than calendula's preferred cool-season range. Buy: Botanical Interests · True Leaf Market · High Mowing Organic Seeds Full notes
- 'Resina': Utah State University Extension notes this variety has high resin content in the blooms, the pick specifically if you're growing calendula for its traditional medicinal/skin-care use rather than as a cutting or bedding flower. Buy: Botanical Interests · High Mowing Organic Seeds Full notes
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing calendula" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 10b calendar · Plan your beds in the Garden Designer →
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Growing Calendula in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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