Polyantha PrimroseItem no. U4100
- Shining Colours
- Uniform series across the whole colour range
- Extremely winter hardy, Crescendo®s can be used much like a pansy in Northern climates
- Sow in July for late January flowering
- Crescendo®s can be grown under cooler temperatures, cutting production costs for the grower
7″ / 18 cm
Partial shade - Shade
Bedding, Potplant, Landscape
- Uses: Attractive pot plants, bedding, cut flower production
- Exposure: Partial shade - Shade
- Garden height: 7″ / 18 cm
- Crop time: 7-9 months
- Sow time: Outdoor forcing: March-May; Indoor forcing (frost free): Mai-June
- Sowing method: 1 seed per plug
- Germination*: 10-14 days at 65 °F (18 °C). Avoid temperatures above 68 °F (18 °C) during germination. Maintain relative humidity above 95 %. Sow seeds in well drained media low in nutrients with a pH between 5.8-6.2. Cover seed lightly with vermiculite. Light plug trays during Stage I.
- Growing On: Transplant plugs into 4-4.5" (10-11 cm) pots containing a well-drained media with a pH range of 5.8-6.5. Grow on at 59-63 °F (15-16 °C) for 3-4 weeks. Fertilize at 100-150 ppm nitrate nitrogen in a well-balanced mix. Maintain light levels below 3000 f.c. until fully rooted. Once established, lower temperatures to 40 °F (5 °C) or lower for 6 weeks to induce uniform flower initiation. Once buds are set, gradually increase temperatures to 50-54 °F (10-12 °C). Avoid excessive temperatures, as poorer plant and flower quality will result.
- 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, 0-3 kg/m³ slow release fertilizer (3-6 months), iron-chelate, micronutrients, pH: 5.8-6.2.
- 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 promotes considerably the flower initiation for a frost free cultivation. The plants start (from CW 45 earliest) to grow for 12-15 weeks at 10-14 °C. Avoid higher temperature, because high temperatures reduce the plant quality and the foliage will grow too much. For cut flower production in cold greenhouse set up the plants in intervals. Flowering pots can be stored in cold storage-room for 4 weeks at 0,5-2 °C.
- Fertilization: Low-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 care of a good potassium supply, because potassium deficiency can a be cause for leaf necrosis. Avoid high ammonium and high nitrogen levels. High levels are the cause for a too big foliage. 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 ferrous fertilizer. For outdoor cultivation nutrition losses due to rainfall have to be taken into consideration.
* Germination Stages (from seed to finished young plant)
Stage I Starts with the radicle breaking through the testa. The roots are touching the medium.
Ends with fully developed cotyledons.
Stage II Starts from fully developed cotyledons. Ends with the fully developed true leaf or true leaf pair.
Stage III Starts from the fully developed true leaf or true leaf pair and ends with 80% of the young plants being marketable.
Stage IV All young plants are ready for sale and in the process of being hardened off. This stage lasts about 7 days.
The cultural recommendations are based on results from trials conducted under Central European conditions. Different conditions in other parts of the world may lead to deviations in results achieved.