The Latest Primrose Cultivation Techniques and Methods Tutorial

Primrose, also known as cowslip, and the annual flower Primula genus is a typical warm-temperate plant; the vast majority of species are distributed in higher-latitude low-altitude or lower-latitude high-altitude areas, preferring a cool, humid climate and well-drained soil rich in humus, and not tolerant of high temperatures or strong direct sunlight, and most are also not tolerant of severe cold.

Propagation Methods

Primroses are mainly propagated from seed, and special horticultural cultivars are also propagated by division or by suckers.

Seed viability is generally short, so it is best sown immediately after harvest, or stored under dry, low-temperature conditions. Sow in a seeding box or shallow pan. Because the seeds are tiny, they may be left uncovered after sowing. The seeds need light to germinate and like moisture, so cover with glass and shade with newspaper, or place in partial shade. Germination is complete in 10 to 28 days. The optimum temperature is 15C to 21C; above 25C the germination rate drops markedly, so the hottest summer season should be avoided. The sowing time depends on the desired flowering period: for winter flowering in a cold greenhouse, sow in late spring; for early spring flowering, sow in early autumn. For flowers for open-ground flower beds in spring, sowing in early autumn is also possible.

Division and suckering are generally carried out in autumn.

Cultivation Techniques

Primrose cultivation and management are not difficult. For types used as greenhouse pot flowers, from sowing to marketing in 12 cm pots takes about 160 days. If sown in July, they can flower at the beginning of the year. To avoid hot weather, sow in August and they can also flower in January. The first transplanting is into shallow pans or wooden boxes, with a plant spacing of about 2 cm, or directly into 8 cm small pots; the potting soil must absolutely not be acidic, and then they are moved directly into 12 cm pots. Planting depth should be moderate: too deep and the roots rot easily, too shallow and the plants lodge easily. Fertilize frequently. Apart from acidic potting soil, the causes of leaf chlorosis may be excessive moisture or poor drainage. Not only should shade be provided in summer, but shade should also be given when the sunlight is strong in winter, to ensure vivid flower colors.

For cold-hardy types, when overwintering outdoors in areas north of the Yangtze River, provide a sheltered spot and give light protection to keep them safe. Sown in August, potted seedlings overwintering in a cold frame can flower and be marketed from February to April.

For transplanting seedlings into pots, pots are generally limited to 12 cm to 16 cm. For 2-year-old old plants, the pots may be appropriately enlarged. During summering, attention should be paid to ventilation, giving partial shade and preventing damage from sudden rain showers, and measures such as misting, overhead frames and watering the ground should be used to lower the temperature. In winter, the minimum indoor night temperature should be kept at about 5C and should not be too high. However, for pot flowers, if sowing is too late (October), the overwintering temperature needs to be raised to 10C in order to speed up growth and ensure timely flowering the following spring.