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Phacelia

Phacelia tanacetifolia
Also known as: Lacy Phacelia, Purple Tansy, Scorpion Weed, Bee's Friend

Phacelia is a cover crop in the Boraginaceae family. It grows best in full sun with dry moisture, and is listed for USDA zones 3-10. Plants reach maturity about 51–69 days after planting and sit about 3 inches apart.

Varieties

1 from High Mowing · sorted by days to maturity
  • Phacelia51–69 days

    Premium pollinator attractant; Interplant between row crops

    Productive flowering cover crop with excellent pollinator attraction. Highly attractive to honeybees, native bees, and syrphid flies, whose larvae are voracious feeders on aphids and young caterpillars. Phacelia is widely adaptable and tolerates drought better than most but requires a dark, cool place for good germination, so bury seed at least ¼ inch deep. Often grown with buckwheat, which acts as a nurse crop for the slower germinating phacelia. Once established, the phacelia takes over the planting and flowers over a long season. Excellent for intercropping between cash crops to attract beneficial predators and pollinators. Seeding rate: 7-12 lbs/acre, 1/4 lb/1000 sq ft.

    Growing notes: We have selected these easy-to-grow flower varieties for their individual beauty, for the beneficial insects they attract, and/or suitability for cut flower production. By offering an assortment of hues, heights, growth habits and appearances, we strive to fill your flower needs, whether you are adding color to your home garden or selling bouquets for market. Our varieties are tried-and-true standards that are sure to perform well in a wide range of growing conditions. Many of these varieties are well suited for succession plantings to ensure a continuous harvest throughout the season. Days to maturity are from seeding. M=1,000.

    View on High Mowing
Family
Boraginaceae
Category
Cover Crop
Form
Stalk
Lifecycle
annual
Zone
3-10
Height
1–3 ft
Spread
0.08333333333333333–0.16666666666666666 ft
Sun
Full sun

Plant spacing

16 plants per square footSquare-foot planting diagram: a 1-foot square divided into a 4-by-4 grid holding 16 phacelia plants spaced 3 inches apart.
16 plants per square foot

In a square-foot bed, space phacelia about 3 in apart — that fits 16 plants in each 1-foot square (4×4). Wider rows or containers space the same.

Water
Dry

Plan your phacelia planting

Add phacelia to a free GardenDraft plan and get sow, transplant, and harvest dates computed for your ZIP code — with a drag-and-drop bed layout and reminders when it’s time to plant.

Start your free plan →

At a glance

Days to harvest
51–69 days
From transplant or sow to first harvest
Harvest style
Harvest once
One main harvest
Frost tolerance
Hardy · to ~20°F
Lowest temperature the foliage usually survives
Succession
Re-sow every 14 days
Sow again at this interval for a continuous harvest

Growing timeline

When to plant and harvest phaceliaPlanting timeline for phacelia, relative to last frost: start indoors from 4 weeks before last frost to around last frost; grow from around last frost to 7 weeks after last frost; harvest from 7 weeks after last frost to 10 weeks after last frost.Start indoorsGrowHarvestLast frostTransplant
Start phacelia indoors ~4 weeks before transplanting around last frost; first harvest 7 weeks after last frost.
Seed to transplant
21-28 days
Outdoor planting
0 days vs frost
Propagation
Seed
Schedule anchor
Last Frost

Care & troubleshooting— extension-sourced, with citations

When to feed, prune & water

Attract beneficial insects and protect pollinators

Protection
  • Routine carePlant insectary flowers and tolerate light pestsstrong evidence — extension confidence

    Grow a diversity of flowering plants (including small-flowered umbels and asters) to feed predators and parasitoids, and tolerate low pest numbers so natural enemies have prey to stick around.

    Source: UC IPM; UMN Extension

  • Routine careNever spray open bloomsstrong evidence — extension confidence

    Avoid insecticides on flowering plants and apply any needed sprays in the evening when pollinators aren't active, and favor selective products over broad-spectrum ones to spare bees and beneficials.

    Source: UC IPM

Something looks wrong?

Describe what you see on your phaceliaand we'll rank the likely causes — most likely first, least-invasive fix first.

Powdery mildew

Diseasemoderate

Symptoms: white powdery coating on upper leaf surfaces; starts as spots then spreads; leaves yellow and dry under the coating

  • CulturalImprove airflow + remove worst leavesstrong evidence — extension confidence

    Cut out the most heavily coated leaves and thin for airflow; avoid wetting foliage late in the day.

    Source: UC IPM

  • OrganicPotassium-bicarbonate or sulfur - label use only· every 1 wk · ~4 wksmoderate evidence — extension confidence

    Apply a labeled potassium-bicarbonate or sulfur fungicide weekly per the label. No sulfur within 2 weeks of oil or in high heat.

    Always follow the product label — it is the law.

    Source: UC IPM

Aphids

Pestlow

Symptoms: clusters of tiny soft-bodied insects on new growth and undersides; sticky honeydew or sooty mold; curled distorted new leaves; ants tending them

  • CulturalBlast off with water· every 3 days · ~2 wksstrong evidence — extension confidence

    Knock colonies off with a strong jet of water in the morning; repeat every few days. Light infestations rarely need more.

    Source: UC IPM: Aphids

  • OrganicInsecticidal soap - label use only· every 1 wk · ~3 wksmoderate evidence — extension confidence

    For persistent colonies apply insecticidal soap to undersides per label. Avoid open flowers.

    Always follow the product label — it is the law.

    Source: UC IPM