Primula Gigas

TECHNICAL INFORMATION

Life Cycle:Perennial

Familiy, Origin:Primulaceae, Northwest Himalaya

Sitelocation:Full sun - partial shade

Garden Height:20 cm,7,87 inch

Natural flowertime:March - April

Crop Time:Plug crop: 8-9 weeks; Green pots: 12-14 weeks; Flowering pots: 12-14 months, including vernalization

Sell Period:December-March

Seed Form:Raw Seed

Seed Count:10000 K/g

Sowing Method:1 seed per plug

Germination:14-21 days at 18-22 °C, in media with very low soluble salt levels and pH: 5.0-6.0. Cover seed lightly with vermiculite after sowing. Keep soil wet (relative humidity: 100 %). Soak seeds in cold-storage room at 14 °C for 8-10 days. Afterwards cultivate the seeds in greenhouse at 18-22 °C and get the seedlings used to light slowly. Avoid direct sunlight by shading seed after sowing.

Plug Culture:From Stage II* reduce the soil moisture, but the plug should not dry out. Do not let soluble salt level rise above 0,50 EC. The roots are very sensitive to high salt levels in substrates. Start fertilization at 50-75 ppm nitrogen in a well balanced formula. During Stage III and Stage IV fertilization levels can be increased to 150-200 ppm.

Growing On:4-6 weeks after sowing transplant 1 plant per plug tray (4x4 cm) or in packs. 8-10 weeks later transplant 1 plant into a pack or pot (10-13 cm). After transplanting keep the tray, because it is possible that more seeds germinate at a later time. Two time transplantation supports root development and young plant quality.

Media:Use a well-drained, growing substrate with 15-30 % clay, 0-20 % parts (e.g. bark, perlite), 0,5-1,5 kg/m3 complete balanced fertilizer, 0-2 kg/m3 slow release fertilizer (3-6 months), iron-chelate, micronutrients, pH: 5.0-6.0.

Photoperiod / Light:Day length neutral plants. Keep light level high. In winter outdoor frozen plants have to be protected against sunlight. Protect the plants in summer against high sunlight, too. In winter supplemental lighting is not necessary, but recommended for good plant quality.

Temperature:Grow at 10-15 °C. In winter indoors frost free at 3-5 °C or outdoors. Outdoor fleece cover needed. For wintering the leaf rosette should be well developed. Alternating temperatures (10-12 °C day- and 1-2 °C night temperature) for 4-6 weeks promote considerably the flower initiation for a frost free cultivation. The plants start to grow at 10-14 °C. Avoid higher temperatures, because higher temperatures will reduce the plant quality and the foliage will grow too large.

Fertilization:Moderate fertilization levels are required. Fertilize the crop weekly with 150-200 ppm nitrogen (at 0 kg/m3 slow release fertilizer in substrate), using a complete balanced fertilizer. In August use a potassium balanced fertilizer (N: K2O-ratio: 1:1,5). Take good care of the potassium supply, because potassium deficiency can a be cause for leaf necrosis. Avoid high ammonium and high nitrogen levels in order to avoid that the foliage grows too large. Prevent magnesium deficiency by applying magnesium sulphate (0,025 %) 1-2 times and in case of iron deficiency apply iron-chelate for 1-2 times. Treat nitrogen deficiency (yellow foliage) with urea foliage fertilization. The roots are sensitive to high salt levels (above 2 g/l) in substrates. Avoid high fertilizer concentrations, it is advisable to fertilize several times with low concentrations weekly. Take care of pH value in substrate and if necessary adjust the pH value in substrate with lime or with acidic fertilizer. For outdoor cultivation nutrition losses due to rainfall have to be taken into consideration.

Cultural Hints:The growth can be well controlled by fertilization and by water supply. Cultivate rather moist and not too close for a good plant quality and plant health. P. rosea needs a higher moisture in substrate than other Primroses. Avoid drought stress.