Centaurea Macrocephala

TECHNICAL INFORMATION

Life Cycle:Perennial

Familiy, Origin:Asteraceae, East and Mid European mountains

Sitelocation:Full sun

Garden Height:125 cm,49,21 inch

Natural flowertime:July - August

Crop Time:Plug crop: 5-6 weeks; Green pots: 12-16 weeks; Flowering pots: 8-10 months, with vernalization; Cut flower production: 5-8 years

Sell Period:April-May and August-October

Seed Form:Raw Seed

Seed Count:61 K/g

Sowing Method:1-6 seeds per plug, directly sown in final pot is possible

Germination:14-21 days at 20-25 °C in media with low soluble salt levels and pH: 5.8-7.0. Cover seed with vermiculite, sand or substrate after sowing. Keep soil slightly moist but not wet. When cotyledons expand, the seed need short day for the vegetative growth.

Plug Culture:From Stage II* reduce the soil moisture, but the plug should not dry out and reduce the temperature to 17-18 °C. Do not let soluble salt level rise above 0,75 EC. 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:3-4 weeks after sowing transplant 1 plant into a pot (8-12 cm) and 2-3 plants into a bigger pot (12-15 cm) or container (3-5 l). Plant cut flowers in 30x40 cm space (C. montana) or in 40x50 cm space (C. macrocephala) and use nets to keep the stems upright for a better flower stems quality.

Media:Use a well-drained, growing perennial substrate with 0-15 % clay, 0-15 % organic parts (e.g. wood fibres, bark, coconut fibris), 1-1,5 kg/m3 complete balanced fertilizer, 2-3 kg/m3 slow release fertilizer (3-9 months), iron-chelate, micronutrients, pH: 5.8-7.0. Field: humus, loamy sandy to sandy loamy soils with a good drainage. Standard fertilization: 100-120 g/m2 slow release fertilizer.

Photoperiod / Light:Long day plants. The long day support the flower initiation while the short day support the vegetative growth. In the early weeks of vegetative growth (in summer or in spring depending on variety) cultivate in short day (10-12 h) until the plants have got the required height. After that cultivate in long day (16-18 h) for flower initiation. In winter additional assimilation light is required.

Temperature:Grow at 10-18 °C. Keep cold night temperatures at 10-12 °C for a better plant quality and for a branch, compact plant shapes. In winter indoors frost free at 3-5 °C or outdoors. In spring the plants start to grow for 7-8 weeks at 15-18 °C. Cold temperatures at 10-15 °C will increase the cultivation time. A chilling period for flower initiation is required. Centaurea can also made to flower 2-3 weeks earlier in poly-tunnel.

Fertilization:Moderate-high fertilization levels are required. Fertilize the crop weekly with 150-200 ppm nitrogen (at 3 kg/m3 slow release fertilizer in substrate), using a complete balanced fertilizer. Avoid high ammonium and high nitrogen levels. Don't fertilize after mid September. In spring fertilize with 150-200 ppm nitrogen of a complete balanced fertilizer. 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. Field: If necessary according to analysis, improve the soil with 50-80 g/m2 slow release fertilizer per year, applied in several portions.

Cut Flowers:Cut flower stems can be harvested, when the pigmentation from flowers are good visible. Vase life: 8-10 days. Cold storage is possible. Dried flower production is possible.

Cultural Hints:Plants, that are growing in greenhouse or poly tunnel are susceptible against pest and diseases. Take care that nutrition and water supply is good.