Lemon Balm in Zone 10a & 10b
Melissa officinalis
Yes, lemon balm grows in zones 10a and 10b. Plant it outside in Feb–Apr. For a fall crop, plant out in Oct–Nov.
When to plant lemon balm 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. It needs a head start most zones can't give it by direct-sowing alone.
| Window | Spring window |
|---|---|
| Start indoors | Not typically started indoors |
| Direct sow / transplant outside | Feb–Apr |
| Estimated harvest | ~65 days after transplanting |
| Window | Fall window |
|---|---|
| Start indoors | Not typically started indoors |
| Direct sow / transplant outside | Oct–Nov |
| Estimated harvest | ~65 days after transplanting |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1.5-2 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 lemon balm for late-summer planting.
Plant alongside it in zone 10b
These go outside within two weeks of lemon balm in zone 10b, so one planting day can cover them.
- BasilFeb–Aug
- RosemaryFeb–Apr
- BorageJan 30–Feb 6
- Marjoram (Sweet)Feb–Apr
- Mint (Spearmint)Feb–Apr
- OreganoFeb–Apr
Lemon balm is a member of the mint family, and it shares mint's biggest garden habit along with its fast growth and pleasant citrus scent: left unchecked, it spreads. If self-seeding is the part that bothers you most, the sterile 'Compacta' cultivar is worth seeking out over a generic packet.
How lemon balm fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Lemon balm needs about 65 days from transplant to first harvest.
Lemon Balm 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 | Harvest |
|---|---|---|---|
| 3a & 3b | Apr 25–May 2 | Jun 6–Jun 13 | Aug 10–Aug 17 |
| 4a & 4b | Apr 10–Apr 17 | May 22–May 29 | Jul 26–Aug 2 |
| 5a & 5b | Apr 5–Apr 12 | May 17–May 24 | Jul 21–Jul 28 |
| 6a & 6b | Mar 21–Mar 28 | May 2–May 9 | Jul 6–Jul 13 |
| 7a & 7b | Mar 6–Mar 13 | Apr 17–Apr 24 | Jun 21–Jun 28 |
| 8a & 8b | Feb 18–Feb 25 | Apr 1–Apr 8 | Jun 5–Jun 12 |
| 9a & 9b | Jan 11–Jan 18 | Feb 22–Mar 1 | Apr 28–May 5 |
| 10a & 10bSpring window (your zone) | Not usually | Feb–Apr | ~65 days after transplanting |
| Fall window | Not usually | Oct–Nov | ~65 days after transplanting |
Harvest dates are about 65 days after the sow or plant-out date, not after starting seeds indoors.
Good companions
No well-established companions for lemon balm.
Where to buy lemon balm seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's lemon balm seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing lemon balm" 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 Lemon Balm in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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