Nigella is an annual grown for its blue blooms, which open from spring through fall. It's hardy across USDA zones 2 through 10 and shrugs off deer. Its flowers are a moderate draw for honeybees and native bees.
Zones
2-10
pH Range
6-8
Sun
Full Sun
Days to Maturity
70
Score Nigella on your exact land.
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What Nigella is
Nigella grows as an annual and reaches around 1.75 feet at maturity. It blooms blue from spring through fall. It's also deer-resistant.
How to grow Nigella
Nigella grows in USDA zones 2 through 10. Nigella does best in full sun — at least 6 hours of direct sun a day — and soil from pH 6 to 8, on well-drained ground. It needs around 900 growing degree days to mature and a growing season of at least 100 frost-free days, which is why climate matters as much as soil.
USDA Zones
2-10
USDA PHZM 2023
Soil pH
6 - 8
USDA PLANTS Database
Sun
Full Sun
Growable Ground plant catalog
Drainage
well (dry spells)
Growable Ground plant catalog
Frost Tolerance
41°F
The lowest temperature it shrugs off — below this, expect damage without cover.
Growable Ground plant catalog
Days to Maturity
70 days
Growable Ground plant catalog
GDD Required
900+
Growing degree-days of accumulated warmth it needs to mature — humid summers reach this faster than cool coastal ones.
Growable Ground plant catalog
Mature Height
1.75 ft
Growable Ground plant catalog
Frost-Free Days
100+
The frost-free stretch it needs start to finish — short-season areas may need an indoor head start.
Growable Ground plant catalog
Start the season right
Plant nigella in full sun with at least 6 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Nigella prefers pH 6 to 8 (FAO ECOCROP). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.
Water steadily
Keep the root zone evenly moist through establishment. A 2–3 inch mulch layer holds moisture without waterlogging.
Harvest at its peak
Cut nigella blooms in the cool of the morning, just as they open, for the longest display.
Good to know
One caution for pet owners — nigella is toxic to dogs and cats (mild severity). Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency. (Source: Pet Poison Helpline.)
Nigella offers moderate value to bees and other pollinators. (Source: Pollinator Partnership.)
Where Nigella thrives
On hardiness alone, nigella grows across most of the country — its range (USDA zones 2 through 10) is unusually wide. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.
Zones 2–10·Where Nigella growsOpen map →
Continental US shown — Alaska and US Pacific territories sit outside the federal map's polygon dataset.
On USDA hardiness-zone overlap, Nigella can grow in these states:
See if Nigella will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether nigella actually takes — we score it against the real conditions at your address.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Frequently Asked Questions
Can I grow Nigella in my zone?
Nigella grows in USDA hardiness zones 2 through 10 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.
When should you plant Nigella?
Most growers plant nigella after the last spring frost, once the soil has warmed, leaving enough of the season for its 100-day frost-free need. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Nigella need?
Nigella needs full sun — a spot that catches at least 6 hours of direct summer sun a day. In more shade it still grows, but usually gives a smaller, later crop. The catch is that a yard rarely gets even light everywhere — a fence, the house, or one tall tree can quietly take those hours. A Growable Ground report reads the real sun-hours across your land, canopy and buildings included, so you can pick the brightest bed before you plant.
What soil does Nigella need?
Nigella prefers soil pH 6 to 8, on well-drained ground (FAO ECOCROP). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Nigella attract pollinators?
Yes — nigella's flowers are a solid nectar source for honeybees and native bees. (Source: Pollinator Partnership.)
Is Nigella safe for pets?
Nigella is toxic to pets (dogs,cats) with mild severity. Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency. (Source: Pet Poison Helpline.)