Four O'Clock in Zone 4a & 4b
Mirabilis jalapa
When to plant four o'clock in zone 4b
Zones 4a and 4b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Four O'Clock doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | May 22–May 29 |
| Estimated bloom | Jul 31–Aug 7 (~70 days after direct-sowing) |
Spacing: about 2 square feet per plant (square-foot-gardening spacing). Mature height: 2-3 ft.
Four o'clocks are named for exactly what they do: the trumpet-shaped flowers, pink, red, yellow, white, or speckled bicolor, stay closed most of the day and pop open in late afternoon, releasing a strong sweet fragrance that carries into the evening. It's a low-effort plant to get started, the seed is large and easy to handle, nothing like the dust-fine seed of many other flowers, but it needs plenty of room once it's growing.
How four o'clock fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Four O'Clock needs about 70 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Four O'Clock.
Where to buy four o'clock seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing four o'clock" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Four O'Clock in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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