Heirloom

Phacelia

Phacelia tanacetifolia

Photo: AnRo0002 · Wikimedia Commons · (CC0)

Most commonly seeded in mass plantings, or as an annual cover crop with nectar-rich blooms to attract and support beneficial and pollinator insects. An excellent, fast-growing, easy-to-grow source of nectar for honeybee forage. Tolerant of low water conditions and poor soils. Used as a cover crop, will winterkill at 18°F (-8°C) - residue breaks down relatively quickly. Furled, lavender-colored flowers with tall, sturdy stems are sometimes used as a cut flower, adding a casual, wildflower look to bouquets. Also commonly known as bee's friend, lacy phacelia, blue tansy, purple tansy, and lacy scorpion-weed. Relative of borage and native to the United States and Mexico. For mass plantings or cover crop, sow at 3 oz./1,000 sq.ft. or 7 lb./acre.

Harvest

45-60d

Days to harvest

📅

Sun

Full sun

☀️

Zones

11–11

USDA hardiness

🗺️

Height

1-3 feet

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Start Indoors

Transplant

Direct Sow

Start Indoors

Transplant

Direct Sow

Showing dates for Phacelia in USDA Zone 7

All Zone 7 flower →

Zone Map

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Phacelia · Zones 11–11

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

SpacingDirect sow at 3 oz./1,000 sq.ft. (for mass plantings/cover crop)

SoilTolerant of poor soils; prefers well-drained conditions

WaterModerate — regular watering

SeasonWarm season annual

ColorLavender

Size3 oz.

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 1	May – June	July – August	July – September	—
Zone 2	April – May	June – July	June – August	—
Zone 11	January – January	January – February	January – March	—
Zone 12	January – January	January – February	January – March	—
Zone 13	January – January	January – February	January – March	—
Zone 3	April – May	June – July	June – August	—
Zone 4	March – April	June – June	June – July	—
Zone 5	March – April	May – June	May – July	—
Zone 6	March – April	May – June	May – July	—
Zone 7	February – March	April – May	April – June	—
Zone 8	February – March	April – May	April – June	—
Zone 9	January – February	March – April	March – May	—
Zone 10	January – January	February – March	February – April	—

Succession Planting

Phacelia blooms for roughly 3–4 weeks per sowing before it sets seed and declines, so staggering direct sowings every 2–3 weeks from April through early June in zone 7 keeps flowers — and the pollinators that follow them — running through midsummer. Sow at 3 oz. per 1,000 sq. ft. each time; starting indoors is only worth the trouble if you're trying to get blooms before your last frost date.

Stop sowing once daytime highs are reliably at 80°F or above. The bloom window shrinks fast in summer heat and you'll get very little out of a July sowing. If you want fall coverage, let the last planting drop seed and mark the spot — volunteers come up on their own schedule and tend to perform better than anything pushed in the hottest part of the year.

Complete Growing Guide

Light: Full sun (6 or more hours of direct sunlight a day). Soil: Sand, Shallow Rocky. Height: 1 ft. 0 in. - 3 ft. 0 in.. Spread: 1 ft. 0 in. - 3 ft. 0 in.. Spacing: 12 inches-3 feet. Growth rate: Rapid. Maintenance: Medium. Propagation: Seed.

Harvesting

Two brown wrinkled seeds are produced in the ovoid fruit. Seeds drop to the ground when the fruit is mature.

Storage & Preservation

Phacelia is primarily grown for ornamental and agricultural purposes rather than culinary use. When harvested as cut flowers, condition stems in cool water immediately after cutting and store in a cool room (65-70°F) with 60-70% humidity; they will last 7-10 days. For seed collection, allow flower heads to dry completely on the plant, then harvest and store seeds in a cool, dry location (below 50°F, low humidity) in sealed containers for up to 3 years. If preserving for cover crop residue incorporation, allow plants to winter-kill naturally or cut and dry plant material before incorporating into soil as green manure.

History & Origin

Origin: California to Mexico

Advantages

+Excellent nectar source attracts honeybees and beneficial pollinator insects efficiently
+Fast-growing cover crop that winterkills easily at 18°F for cleanup
+Tolerant of poor soils and low water conditions without special care
+Attractive lavender flowers work well as casual, wildflower-style cut flowers
+Easy to establish and maintain with minimal growing difficulty

Considerations

-Dies in cold winters, limiting use in northern climates permanently
-Self-seeds aggressively if allowed to flower, potentially becoming weedy pest
-Requires timely mowing to prevent excessive reseeding in subsequent seasons

Companion Plants

Phacelia is one of the better pollinator draws you can put near fruiting crops. Its nectar-rich flowers pull in hoverflies (family Syrphidae) and parasitic wasps that hunt aphids and caterpillars — which is why it belongs near tomatoes, cucumbers, and beans. Those crops benefit from both stronger pollination and reduced pest pressure at the same time. Carrots and cabbage get a similar payoff: hoverflies working the phacelia blooms also deposit eggs near aphid colonies on brassicas and umbellifers, giving you some biological control you didn't have to spray for. Marigolds and sunflowers are easy neighbors with no territorial drama — similar water needs, no meaningful root competition.

Black walnut, eucalyptus, and fennel are the ones to plant well away from. Black walnut produces juglone, a root-exuded compound that suppresses a wide range of annuals. Fennel is broadly allelopathic — it stunts most plants that grow within a foot or two of it, and phacelia is no exception. Eucalyptus releases growth-inhibiting compounds through both its roots and fallen leaves. None of these are worth working around; just keep phacelia in a different part of the garden entirely.

Plant Together

Tomatoes

Phacelia attracts beneficial insects that control tomato hornworms and other pests

Cucumbers

Attracts pollinators and predatory insects that help with cucumber beetle control

Beans

Phacelia attracts beneficial wasps that parasitize bean pests like aphids

Carrots

Attracts hoverflies and parasitic wasps that control carrot fly and aphids

Cabbage

Draws beneficial insects that prey on cabbage worms and flea beetles

Strawberries

Attracts pollinators to improve fruit set and predators for pest control

Sunflowers

Both attract similar beneficial insects creating a strong pollinator habitat

Marigolds

Complementary pest control through different beneficial insect attraction

Keep Apart

Black Walnut

Produces juglone which inhibits growth of many plants including Phacelia

Eucalyptus

Releases allelopathic compounds that suppress growth of nearby plants

Fennel

Produces allelopathic compounds that inhibit germination and growth of most garden plants

Troubleshooting Phacelia

What you'll see, why it happens, and what to do about it.

Seedlings damping off at soil level within the first 10 days after germination

Likely Causes

Pythium or Rhizoctonia fungi — triggered by overwatering and poor drainage
Sowing too thickly (above 3 oz./1,000 sq. ft.) so seedlings crowd and hold moisture against stems

What to Do

1.Thin aggressively as soon as seedlings emerge — crowding is the main driver here
2.Water in the morning so the soil surface dries before nightfall
3.If starting indoors, use a sterile seed-starting mix and don't let trays sit in standing water

Leaves with pale, stippled patches and fine webbing on the undersides during hot, dry spells

Likely Causes

Two-spotted spider mite (Tetranychus urticae) — populations explode when temperatures stay above 85°F and humidity is low

What to Do

1.Hit the undersides of leaves with a strong spray of water to knock mites off — do this three days in a row
2.Apply insecticidal soap or neem oil in the evening so it doesn't evaporate before contact
3.Keep soil consistently moist; drought-stressed plants draw mites faster than well-watered ones

Powdery white coating on leaves and stems, usually appearing after day 40 as plants mature

Likely Causes

Powdery mildew (Erysiphe cichoracearum) — common on phacelia late in the season, especially where airflow is poor
Overhead watering at night that leaves foliage wet for hours

What to Do

1.Cut out the worst-affected stems at the base and put them in the trash, not the compost pile
2.Switch to drip or base watering if you've been wetting the foliage
3.A baking soda spray (1 tablespoon per gallon of water) can slow spread if caught early, though it won't reverse existing infection

Plants flowering and going to seed well before the 45–60 day mark, with sparse, stunted foliage

Likely Causes

Heat stress — phacelia rushes to seed when daytime temperatures consistently exceed 80–85°F
Sowing too late so plants hit summer heat before they've sized up

What to Do

1.Direct sow no later than early June in zone 7; anything after that and the plants bolt before they've done much for you
2.For a late planting, choose a spot with afternoon shade to stretch the bloom window by a week or two
3.Let the last planting go to seed in place — phacelia reseeds reliably, and those volunteers will hit the ground at a better time than a forced midsummer sowing

Frequently Asked Questions

How long does phacelia take to flower?▼

Phacelia flowers within 45-60 days from seeding, making it an excellent fast-growing option for quick cover crop establishment and pollinator attraction. In ideal warm conditions with full sun and regular moisture, flowering may occur on the faster end of this range.

Is phacelia good for beginners?▼

Yes, phacelia is rated as easy to grow and highly recommended for beginners. It tolerates poor soils and low water conditions, requires minimal care, and grows quickly. Simply direct sow in full sun and let it thrive—no special expertise needed.

When should I plant phacelia?▼

Direct sow phacelia after the last frost date once soil is workable. It thrives in cool to warm weather and can be succession-sown for continuous bloom. In warmer climates, spring and early summer plantings work best; it will winterkill at 18°F, limiting winter planting in cold regions.

What is phacelia used for?▼

Phacelia serves multiple purposes: it's an excellent nectar source for honeybees and beneficial pollinators, making it popular in pollinator gardens. It's also widely used as a cover crop and green manure to improve soil, and its lavender-colored flowers with sturdy stems work as casual, wildflower-style cut flowers.

Can you grow phacelia in containers?▼

While phacelia can technically be grown in containers, it's not ideal since it's typically mass-planted and grows tall with sturdy stems. For best results and to maximize its pollinator benefits, direct sow in garden beds or fields with full sun (6+ hours daily).

Why is phacelia called a cover crop?▼

Phacelia is used as a cover crop because it grows quickly, tolerates poor soils, and winterkills at 18°F, allowing residue to break down relatively quickly when incorporated into soil. It improves soil structure and organic matter while preventing erosion and suppressing weeds.