Sempervivum Hardy Perennial Species

TECHNICAL INFORMATION

Life Cycle:Perennial

Familiy, Origin:Crassulaceae, Europe

Sitelocation:Full sun

Garden Height:5 cm,1,97 inch

Natural flowertime:June - August

Crop Time:Plug crop:11-12 weeks; Green pots: 16-20 weeks; Flowering pots: 8-10 months, including vernalization

Sell Period:March-May

Seed Form:Raw Seed

Seed Count:15625 K/g

Sowing Method:3-5 seeds per plug

Germination:9-14 days at 22-24 °C, in media with very low soluble salt levels and pH: 5.5-7.0. Requires light for germination. Before sowing treat substrate with fungicide against Rhizoctonia. Cover seed lightly with vermiculite after sowing. Keep soil slightly moist but not wet.

Plug Culture:From Stage II* reduce the soil moisture, but the plug should not dry out and reduce the temperature to 18 °C. Do not let soluble salt level rise above 0,5 EC. Start fertilization at 50 ppm nitrogen in a well balanced formula. During Stage III and Stage IV fertilization levels can be increased to 100 ppm.

Growing On:6-8 weeks after sowing transplant 1-3 plants per plug tray (3x3 cm) and 6-8 weeks later transplant 1-3 plants into a pot (9-10 cm) and 3-5 plants into a bigger pot (11-15 cm). Avoid very large pots, because the substrate in pots that are too large will be permanently wet and wetness can cause growth inhibition and a poor root development.

Media:Use a well-drained, growing substrate with 0-15 % clay, 0-15 % parts (e.g. bark, wood fibres, perlite, sand),1-1,5 kg/m3 complete balanced fertilizer, 1-2 kg/m3 slow release fertilizer (3-9 months), iron-chelate, micronutrients, pH: 5.5-7.0.

Photoperiod / Light:Long day plants. For flower initiation and flower development long day (14-16 h) is required. In winter and in early spring additional assimilation light or photoperiodic light is recommended in combination with warm cultivation temperatures of 15-18 °C. High sun light intensity combined with cool temperatures improve the leaf coloring.

Temperature:Grow at 10-18 °C or outdoors. In winter indoors frost free at 3-5 °C or outdoors. Outdoor fleece cover needed. For wintering the roots development should be very good. In spring the plants start to grow for 10-12 weeks at 15-18 °C. Cold temperatures of 10-12 °C will increase the cultivation time. A chilling period (vernalization) is required for flower initiation.

Fertilization:Low-moderate fertilization levels are required. Fertilize the crop weekly with 80-100 ppm nitrogen (at 2 kg/m3 slow release fertilizer in substrate), using a complete balanced fertilizer. Avoid high ammonium and high nitrogen levels. Very high nitrogen levels in substrate cause shoot stretching and the shoots fall apart. Don't fertilize after mid September. In spring fertilize 80-100 ppm nitrogen of a complete balanced fertilizer. Prevent magnesium deficiency by applying magnesium sulphate (0,05 %) 1-2 times and in case of iron deficiency (above pH 6.0) apply iron-chelate for 1-2 times.

Cultural Hints:The growth is very slowly. Avoid algae growth on the substrate surface. Cultivate rather dry. The roots are very sensitive to wet substrates. Short time wetness can cause rotting of roots and a poor plant quality. Avoid over head irrigation, in order to avoid fungi infection of the leaf rosettes.