Phacelia: when and how to sow, cultivation and benefits

Phacelia is a genus of herbaceous annuals and perennials of the Waterwort family, which according to various information includes from 80 to more than 180 species growing in South and North America in open sunny places with well-drained soil. The name of the genus comes from the Greek word meaning “bunch”: this is what the inflorescence of phacelia looks like. In culture, the species Phacelia citrifolia is grown primarily as a green manure.

The useful properties of phacelia improve the structure of the soil and enrich it with nutrients. Several species of the genus have proven themselves as decorative garden plants. In addition, phacelia grass is an excellent honeybee, attracting bees and other insect pollinators to the garden.

Botanical description

Phacelia apex, or Ryazan phacelia, is an annual plant over 1 m tall, covered with bristly pubescence. The stem is erect, with glandules, each bush develops up to 20 lateral shoots. Radical oblong pinnately dissected leaves reach 6 to 20 cm in length and 3 to 15 cm in width; they consist of lanceolate, pinnately dentate leaflets. The stem leaves are usually sessile, but may be arranged on the stem on short petioles.

Numerous bluish-lilac broad-bell-shaped flowers up to 10 mm long forming intricate cymolla-shaped umbrellas. Stamens up to 14 mm long protrude strongly from the corolla and consist of glabrous filaments and oblong elliptical anthers. The fruit of the phacelia is a broadly ovate capsule up to 5 mm long with a pair of dark brown wrinkled seeds.

The honeydew phacelia is a universal siderat: it can be sown both after and before any crop, while after mustard, for example, cruciferous plants cannot be grown on the plot. However, winter-hardy phacelia grows green mass much faster than other green manure plants and protects the plot from weeds. It enriches the soil with potassium and nitrogen and makes it less acidic.

Growing phacelia as a green manure

When to sow in the soil

Phacelia as a siderat has a wide popularity among gardeners and vegetable growers. The timing of its sowing is determined by the goals you pursue:

• if you sow the culture immediately after snowmelt, the seedlings appear in two weeks quickly build up green mass, which allows you to get excellent humus after mowing the grass, provided the grass is shallowly embedded in the soil or mulch, if the grass remains lying on the surface;
• If phacelia is used as a honeybee, it is planted between the rows of other crops throughout the season. In this case, the wilted grass is mowed and used as fertilizer or as mulch, and the next sowing is done on vacant plots;
• sowing phacelia after the harvest from late summer to mid-autumn restores and revitalizes the soil, improves its composition and saturates it with nutrients. If you leave the cuttings on the surface of the plot as mulch, they protect the roots of perennial plants from freezing and the soil from erosion and washout of useful substances by autumn rains;
• When sown under the winter, phacelia gives early sprouts in the spring, which are cut before planting of early-ripening varieties of the main crop. In this case, sow phacelia much more densely, because after the cold winter, not all seeds may germinate.

How to sow

With good germination, the seeds of phacelia do not need to be pre-stratified. They are scattered over the plot in the loosened soil with a rake. Dark phacelia seeds are not visible on the soil surface and can better be mixed with dry sand before sowing to avoid leaving any germination areas.

If you are sowing phacelia between the rows of the main crop, make a groove 2-3 cm deep, moisten it with water, spread the seeds evenly, and then sow them in. If it’s not too hot and dry, you don’t need to water the furrow after sowing.

Care for Phacelia

Phacelia needs moisture only at the seed germination stage, but with early spring sowing the soil is well saturated with moisture, and you do not have to water it. In a season with average rainfall, natural precipitation is quite enough for the phacelia, so you only need to moisten the area during a prolonged drought. Otherwise, the care of the growing green manure involves only occasional shallow loosening of the soil.

Organic fertilizers Optim-Gumus, Baikal EM-1, Bokashi, Siyaniye-1, which contain effective soil microorganisms, will help you get a rich harvest of green mass of phacelia. Apply them in strict accordance with the instructions.

Mow phacelia siderata in the phase of formation of buds. If you delay mowing, the leaves and stems have time to coarsen and will decompose much more slowly, and the longer the process of decomposition, the more harmful to the soil and plants develop in the decaying mass. Mowed phacelia is digged up with the top layer of soil, pre-treated with a product that accelerates processing. Facelia decomposition and further humification of the soil occurs only in the presence of moisture, so in the absence of precipitation it is necessary to irrigate the site.

After embedding the green manure, the surface is levelled and reseeded with phacelia. Thus, in one season you can grow 3-4 crops of green manure, and the next spring use this area with renewed nutritious soil for growing vegetables.

Pests and diseases

Phacelia not only has a high resistance to any pests and infections, but is also able to protect the neighboring crops from them. For preventive purposes, plant phacelia in mixed plantings, interspersing its rows with rows of vegetables that do not have such resistance.

Species and varieties

In addition to phacelia cinquefoil, the description of which we gave at the beginning of the article, other species of the plant are also grown in culture, but more for ornamental purposes.

Phacelia argentea

Grows on the dunes and coastal sand slopes of northern California. It is a rare species of Phacelia with ascending and drooping stems up to 50 cm tall, with shiny and silvery white leaves and globular heads of small white flowers.

Phacelia bolanderi.

Grows in the “redwood” forests of California, forming low mounds of worm-like spreading stems. Phacelia blooms with large, arcing hanging lavender-blue bell-shaped flowers that form terminal inflorescences.

Phacelia lancewort (Phacelia hastata).

Found in the United States in coniferous forests and wormwood thickets. This plant grows to a height of up to 50 cm. It has small, pale purple or white flowers. Dense silvery hairs and nearly parallel veins on the surface of the leaves are characteristic of the species.

Phacelia sericea.

Found in North America from New Mexico to Utah and from Alaska to Colorado. It is a popular cultivated plant covered with delicate silky silvery hairs, with one or more unbranched stems up to 45 cm high and deeply incised leaves. Blue, lavender or purple flowers with long stamens make this species resemble a lupin or monardia.

Phacelia campanularia.

Phacelia campanularia or California bellflower is a 25 cm tall annual from southern California. Its stems are reddish, erect and brittle. The faint blue-green leaves are up to 6 cm long with a red-brown border around the edges, arranged on petioles. Dark blue bell-shaped flowers up to 3 cm in diameter with dark spots at the base are formed into unilateral cotyledonous inflorescences.

Phacelia congesta.

A species with very small blue flowers, which grow no larger than 5 mm in diameter and which are held together at the stem tips in twisted inflorescences. Shoots up to 50 cm long are covered with light green, dense pubescent leaves.

Phacelia purshii.

A plant up to 50 cm tall with densely pubescent leaves and small flowers up to 3 cm in diameter, the corolla white on the inside with purple spots on the outside. The latest achievement of breeders.

In addition to the above species, Phacelia multifoliata, Phacelia fulvirensis and Phacelia lajellus can also be found in cultivation.