Calendula in Zone 3a & 3b
Calendula officinalis
When to plant calendula in zone 3b
Zones 3a and 3b share the same average frost dates in our data, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Calendula tolerates either.
| Start indoors | Apr 11–Apr 18 |
|---|---|
| Direct sow / transplant outside | May 16–May 23 |
| Estimated bloom | Jul 5–Jul 12 (~50 days after planting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
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 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Calendula needs about 50 days from sowing to first harvest.
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 actually shows, so treat calendula as a general aphid-predator draw near tomatoes rather than a hornworm-specific one.
Where to buy calendula seeds
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 3b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Calendula in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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