Lacy Phacelia

Phacelia tanacetifolia, commonly known as lacy phacelia or blue tansy, is a fast-growing hardy annual prized as both a cover crop and pollinator plant. Its finely divided, fernlike foliage and masses of lavender-blue, bell-shaped flowers attract honeybees, native bees, and syrphid flies whose larvae prey on aphids. It is widely used in organic growing as a green manure, and the leafy biomass is cut and worked into the soil before seeds ripen. Phacelia self-seeds readily and tolerates drought better than most cover crops.

Growing

Broadcast or drill seed directly into prepared ground once soil temperature reaches 5 °C. Sow at 1 cm depth and rake lightly to cover — good seed-to-soil contact and darkness are essential for germination. Space or thin plants to around 15 cm apart. Phacelia can be sown successionally as soil conditions allow. It requires no indoor start and establishes rapidly from direct sowing.

Care

Water after sowing to establish, then rely on rainfall; phacelia tolerates dry spells well. No feeding is required — excess nitrogen promotes leafy growth at the expense of flowers. Avoid disturbing roots once established. If self-seeding is unwanted, cut plants at the base before seeds fully ripen. No staking is needed for shorter sowings; tall plants in rich soil may lean in wind.

Harvest

As a green manure, cut the entire plant at the base just as flowering reaches its peak, before seeds set. Chop the stems and leaves and incorporate them directly into the soil, or use as a mulch elsewhere. For pollinator benefit, allow flowering to continue as long as bees are actively working the blooms, then cut before seed heads shatter. Collect ripe seed heads in a paper bag if saving seed.

In the kitchen

Phacelia is not grown for culinary use. Its value lies in soil improvement, pollinator attraction, and aphid biocontrol via the syrphid flies it hosts. The flowers are technically edible but are not a culinary ingredient in established use.

Storing

Store dried seed in a cool, dry, dark location in a sealed paper or cloth bag. Seeds remain viable for 2–3 years under these conditions. There is no food storage application for this crop.