Crocus in Zone 4a & 4b
Crocus spp.
When to plant crocus 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. Crocus doesn't transplant well, or doesn't need the extra time indoors.
| Window | Fall window |
|---|---|
| Start indoors | Not typically started indoors |
| Direct sow / transplant outside | Sep–Nov |
| Estimated bloom | Jan 29 '27–Apr 29 '27 (~150 days after direct-sowing) |
Spacing: 12 per square foot (square-foot-gardening spacing). Mature height: 3-6 in.
Zone 4b dates sourced from www.longfield-gardens.com.
Crocus is grown from a corm, not a bulb, and it's usually the very first thing to bloom in the garden, sometimes pushing up through late snow in early spring, weeks before daffodils or tulips get going. The whole plant is small, just 3 to 6 inches, with cup-shaped blooms in purple, yellow, or white.
How crocus fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Crocus needs about 150 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Crocus.
Where to buy crocus bulbs
We haven't vetted bulb/tuber suppliers yet. Our seed-supplier list below doesn't carry these. The growing-guide source cited above is a good starting point for where to buy.
See it growing
Search YouTube for "growing crocus" 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 Crocus in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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