Phacelia
The blue-violet flowers of phacelia, gathered in delicate curling clusters, are an irresistible magnet for bees and other pollinators — and a charming addition to any ornamental bed.
About the variety. A vigorous annual reaching 50–100 cm in height. It produces nectar in exceptional quantities and is considered one of the best bee plants. The flowers are edible. It adapts very well to poor soils and sunny locations. Suitable for containers.
Itinerário técnico
Um guia de cultivo passo a passo, da sementeira à colheita.
Broadcast over worked soil and rake lightly to cover the seed with two or three centimetres of earth. Sow generously, because the aim is to cover the ground completely and leave no room for weeds. Sow in late summer or autumn to cover the winter, or in spring for a short cover between crops. Water after sowing if the soil is dry.
It grows in any soil, poor and compacted ground included, which is exactly where it is most needed, at a pH between 6.0 and 7.5. It needs no feeding: its role is to improve the soil, structuring the ground with its roots, catching nutrients that would otherwise leach away and shielding the surface from rain and sun.
Very tough and adaptable, between 10 °C and 25 °C. In southern Europe the useful window is autumn and winter, when there is rain and the soil would otherwise lie bare. In France and Germany sow from late summer to early autumn, so the cover establishes before the cold. Sow while the soil is still warm, so the crop covers the ground within three or four weeks: a late sowing, with the cold already in, comes up thin and does not do its job. The same calendar applies in Italy: conditions in the centre and south are close to those of southern Portugal and Spain, and those of the north to central France. In spring, sow as soon as the ground can be worked and cut before the June heat, because after that the material turns woody and the plant runs to seed.
It is not a legume: it fixes no nitrogen and, unlike vetches and clovers, does not enrich the soil in nitrogen by itself. What it does is take up the nitrogen and phosphorus already there, hold them in its green matter and hand them back to the following crop when you dig it in, rather than letting them wash away with the winter rain. Sow it by preference after a hungry crop that has left fertiliser behind. It needs no feeding at all.
Water only to secure germination. Once established it needs no irrigation in almost any situation and lives on rainfall. A green manure that is watered heavily loses much of its point.
Sown densely, the crop covers the soil itself and keeps weeds well in check. The work is concentrated in the first two or three weeks: hand weed or run a hoe very shallowly between the plants. Avoid disturbing the soil once the canopy closes, so you do not damage roots or bring fresh weed seed to the surface.
It has practically no relevant pests and instead shelters beneficial insects and pollinators through the off season. Watch only for slugs at the seedling stage and for birds, which eat seed left on the surface: cover the seed properly when sowing. Rabbits and pigeons like the tender seedlings: in a small garden, light netting for the first three weeks stops you losing the sowing. Aphids can appear at flowering in dry years, but rarely justify treatment: the ladybirds deal with them.
Disease is not usually an issue. The important precaution is rotational: choose a species outside the family of the crop that follows and of the one that has just left, so you do not multiply soil borne disease. After brassicas, for example, avoid mustard and fodder turnip. In very dense sowings and wet winters collar rot can appear: do not water and do not sow thicker than recommended.
Let it flower: phacelia is one of the best bee plants there is, and flowering lasts four to six weeks, with the bees on it from morning to night. Cut a few stems for the vase when the first flowers of the coil open, and remove faded ones if you want to extend flowering. If you use it as a green manure, cut and incorporate at the start of flowering, before seed forms, because it self-seeds readily. Allow about 65 to 85 days from sowing to flowering for this variety. The reference colour is purplish blue, and that is what tells you it is ready.
