Phacelia is a cover crop — grown to build and protect the soil rather than for a harvest of its own. It's hardy across USDA zones 2 through 11 and shrugs off deer. Its early spring flowers are a real draw for honeybees, native bees, and butterflies.
Zones
2-11
pH Range
6.4-8.6
Sun
Full Sun
Days to Maturity
45
Score Phacelia on your exact land.
Zone averages can't see the slope, soil, frost, and sun that decide whether phacelia actually takes — and those shift from one yard to the next. Enter your address and we'll score phacelia against your land's real conditions.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
What Phacelia is
Phacelia grows as an annual and reaches around three feet at maturity. It blooms blue in early spring. It's also deer-resistant.
How to grow Phacelia
Phacelia grows in USDA zones 2 through 11. Phacelia does best in full sun — at least 6 hours of direct sun a day — and soil from pH 6.4 to 8.6, on well-drained ground. It needs around 1,000 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
2-11
USDA PHZM 2023
Soil pH
6.4 - 8.6
USDA PLANTS Database
Sun
Full Sun
plant_species_v5.csv
Drainage
well (dry spells)
plant_species_v5.csv
Frost Tolerance
52°F
plant_species_v5.csv
Days to Maturity
45 days
Lacy phacelia; pollinator-friendly cover crop; winterkill cover.
SARE; USDA-NRCS
GDD Required
1000+
plant_species_v5.csv
Mature Height
3 ft
plant_species_v5.csv
Frost-Free Days
100+
plant_species_v5.csv
Start the season right
Plant phacelia in full sun with at least 6 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Phacelia prefers pH 6.4 to 8.6 (USDA PLANTS Database). 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.
Turn it in before it seeds
Cut phacelia down or turn it into the soil before it sets seed, while the growth is still green — that's when it returns the most to the ground.
Good to know
Good news for pet owners — phacelia isn't known to be toxic to dogs or cats. (Source: ASPCA.)
Phacelia is a standout pollinator plant — high value to bees and other pollinators. (Source: Xerces Society, Pollinator Partnership.)
Where Phacelia thrives
On hardiness alone, phacelia grows across most of the country — its range (USDA zones 2 through 11) 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 2–11·Where Phacelia growsOpen map →
Continental US shown — Alaska and US Pacific territories sit outside the federal map's polygon dataset.
On USDA hardiness-zone overlap, Phacelia can grow in these states:
See if Phacelia will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether phacelia 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.
25+ data sources analyzed in seconds
Frequently Asked Questions
Can I grow Phacelia in my zone?
Phacelia grows in USDA hardiness zones 2 through 11 (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 Phacelia?
Most growers plant phacelia 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 Phacelia need?
Phacelia 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 Phacelia need?
Phacelia prefers soil pH 6.4 to 8.6, on well-drained ground (USDA PLANTS Database). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Phacelia attract pollinators?
Yes — phacelia's flowers are a strong nectar and pollen source for honeybees, native bees, and butterflies (Xerces Society, Pollinator Partnership).
Is Phacelia safe for pets?
Phacelia is not known to be toxic to dogs or cats based on available data (ASPCA). Always supervise pets around new plantings.