Phacelia (Lacy Phacelia) in Zone 5a & 5b
Phacelia tanacetifolia
Yes, phacelia (lacy phacelia) grows in zones 5a and 5b. Plant it outside Apr 19–Apr 26.
When to plant phacelia (lacy phacelia) in zone 5b
Zones 5a and 5b share the same average frost dates, so this page covers both.
Method: Direct sow: Direct-sow outside. It doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | Apr 19–Apr 26 |
| Estimated bloom | Jun 28–Jul 5 (~70 days after direct-sowing) |
Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 2.5-3.5 ft.
Plant alongside it in zone 5b
These go outside within two weeks of phacelia (lacy phacelia) in zone 5b, so one planting day can cover them.
- Black-Eyed SusanApr 19–Apr 26
- Clarkia (Farewell-to-Spring)Apr 19–Apr 26
- Cynoglossum (Chinese Forget-Me-Not)Apr 19–Apr 26
- Purple ConeflowerApr 19–Apr 26
- Saponaria (Soapwort)Apr 19–Apr 26
- Shasta DaisyApr 19–Apr 26
Phacelia, also called purple tansy or lacy phacelia, is grown less for cutting than for what it does in the garden: it's an outstanding nectar source for honeybees and draws beneficial insects reliably wherever it's planted.
How phacelia (lacy phacelia) fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Phacelia (lacy phacelia) needs about 70 days from sowing to first bloom.
Phacelia (Lacy Phacelia) planting windows in every zone
Zone 5b 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 | Not usually | Apr 29–May 6 | Jul 8–Jul 15 |
| 3a & 3b | Not usually | May 9–May 16 | Jul 18–Jul 25 |
| 4a & 4b | Not usually | Apr 24–May 1 | Jul 3–Jul 10 |
| 5a & 5b (your zone) | Not usually | Apr 19–Apr 26 | Jun 28–Jul 5 |
| 6a & 6b | Not usually | Apr 4–Apr 11 | Jun 13–Jun 20 |
| 7a & 7b | Not usually | Mar 20–Mar 27 | May 29–Jun 5 |
| 8a & 8b | Not usually | Mar 4–Mar 11 | May 13–May 20 |
| 9a & 9b | Not usually | Jan 25–Feb 1 | Apr 5–Apr 12 |
| 10a & 10b | Not usually | Jan 9–Jan 16 | Mar 20–Mar 27 |
| 11a & 11b | Not usually | Dec 11–Dec 18 | Feb 19–Feb 26 |
Bloom dates are about 70 days after the sow or plant-out date.
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
No well-established companions for phacelia (lacy phacelia).
Where to buy phacelia seeds
True Leaf Market · High Mowing Organic Seeds (each supplier's phacelia seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing phacelia (lacy phacelia)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 5b calendar · Plan your beds in the Garden Designer →
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Growing Phacelia (Lacy Phacelia) in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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