Zinnia in Zone 10a & 10b
Zinnia elegans
Yes, zinnia grows in zones 10a and 10b. Start seeds indoors in Feb–May and plant out in Mar–Jul.
When to plant zinnia 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 | Spring window |
|---|---|
| Start indoors | Feb–May |
| Direct sow / transplant outside | Mar–Jul |
| Estimated bloom | ~65 days after transplanting |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-4 ft.
Zone 10b dates sourced from growinginthegarden.com.
Plant alongside it in zone 10b
These go outside within two weeks of zinnia in zone 10b, so one planting day can cover them.
- Angelonia (Summer Snapdragon)Mar–Jul
- Coreopsis (Tickseed)Mar–May
- CosmosMar–Jun
- Four O'ClockMar–Jun
- Gomphrena (Globe Amaranth)Mar–Jul
- Portulaca (Moss Rose)Mar–Jun
Zinnias are about as forgiving as annual flowers get: direct-sow them after frost, give them sun, and they bloom fast and heavily with almost no fuss, throwing up daisy or dahlia-form flowers in almost every color except true blue on plants anywhere from 1 to 4 feet tall. They've also earned their spot in a vegetable garden on merit. They're one of the better-documented pollinator draws for nearby crops, beyond their good looks as a border filler.
How zinnia fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Zinnia needs about 65 days from sowing to first bloom.
Zinnia 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 22–Apr 29 | May 27–Jun 3 | Jul 31–Aug 7 |
| 3a & 3b | May 2–May 9 | Jun 6–Jun 13 | Aug 10–Aug 17 |
| 4a & 4b | Apr 17–Apr 24 | May 22–May 29 | Jul 26–Aug 2 |
| 5a & 5b | Apr 12–Apr 19 | May 17–May 24 | Jul 21–Jul 28 |
| 6a & 6b | Mar 28–Apr 4 | May 2–May 9 | Jul 6–Jul 13 |
| 7a & 7b | Mar 13–Mar 20 | Apr 17–Apr 24 | Jun 21–Jun 28 |
| 8a & 8b | Feb 25–Mar 4 | Apr 1–Apr 8 | Jun 5–Jun 12 |
| 9a & 9b | Jan 18–Jan 25 | Feb 22–Mar 1 | Apr 28–May 5 |
| 10a & 10bSpring window (your zone) | Feb–May | Mar–Jul | ~65 days after transplanting |
| 11a & 11b | Dec 4–Dec 11 | Jan 8–Jan 15 | Mar 14–Mar 21 |
Bloom dates are about 65 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: Attracts pollinators and hoverflies that improve fruit set and help control aphids.
- Cucumber: Attracts pollinators that improve fruit set.
Where to buy zinnia seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's zinnia seeds)
Varieties we recommend, and where to get them:
- 'Profusion' series: A different species cross (Zinnia marylandica), 12 inches tall and 20-24 inches wide, that University of Wisconsin-Madison Extension notes for strong heat, drought and disease tolerance. Buy: True Leaf Market Full notes
- Queeny Lime with Blush (best for cut-flower color): Johnny's grows this Queeny series pick to 30-40 inches with mostly double, 2- to 3.5-inch blooms in a lime-green-and-blush color combination unlike any of the three series above. Buy: Burpee Full notes
- Double Zahara Salmon (best for containers, powdery mildew): Johnny's Zahara series stays compact at 12-20 inches with a low, mounding habit and is specifically bred for powdery mildew resistance, the disease this profile flags as zinnia's main problem. Buy: Burpee Full notes
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing zinnia" 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 Zinnia in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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