Primula is a genus of 400 species, and the ones that we grow in our gardens are divided into 3 main groupings: Auricula primulas, Candelabra primulas and Primrose-Polyanthus primulas. They prefer cool temperatures, a rich humus soil with lots of compost and leaf mold, and partial shade. They appreciate full sun in the spring, but must have semi shade as the temperatures warm. They are quite tolerant of being transplanted, even when they are in bloom. Will do well beneath trees, shrubs or hedges. Divide every three years after flowering. Deadhead primrose regularly to prolong flowering.
Primroses can be propagate from seeds. The seeds of Primroses are very tiny. They should be surface-sown in a tray in early spring as the seeds need light to germinate, so do not cover them with soil, but a sheet of clear plastic or glass placed over the tray will help to retain the moisture until the seeds sprout, then remove the sheet. Transplant the seedlings into individual pots when they are 5 cm tall. They will be ready to bloom the following spring.
You can also propagate primroses by dividing them from autumn to early spring or by rooting basal cuttings or offsests in autumn or early spring. You can also try to take root cuttings when the plants are dormant in winter.
Newly purchased primroses may be plant in the garden in early spring and older plants may be divided and transplanted right after they are finished blooming. Primroses need to be planted so that their crown is right at soil level, and at least 15 cm apart one of other. They should be planted in a cool, partly shady site in the garden, with rich, well-draining, slightly acid soil (pH 6.5).
Primroses may also be grown indoor if you can provide them cool night temperatures of 10-15 Celsius degrees (50-60 F), high humidity, filtered sun light and moist soil. Daytime temperatures must always remain below 26 Celsius degrees (80 F). After they have finished blooming in the house it is best to plant them directly into the garden, or just take them out over summer in their pots and then moved them back into the house at the end of the season.