Ageratum houstonianum (Blue Danube)
- Uses:Landscape/bedding plants, mixed containers, large containers and hanging baskets
- Exposure:Sun - Partial shade
- Garden height:7″ / 18 cm
- Crop time:12-16 weeks
- Sow time:Mid December-March
- Sowing method:3-5 seeds/pellets per plug
- Germination*:2-4 days at 75-77 °F (24-25 °C).
- Growing On:Grow on at temperatures of 60-68 °F (15-20 °C).
- Media:Use a well-drained, growing substrate with 20-30 % clay, 1-1,5 kg/m³ complete balanced fertilizer, 0-2 kg/m³ slow release fertilizer (3-6 months), iron-chelate, micronutrients, pH 5.5-6.0
- Temperature:Grow at 16-20 °C (64-68 °F). Temperatures below 16 °C (64 °F) delay flowering and below 10 °C (50 °F) cause chlorosis. Ageratum does not tolerate frost.
- Fertilization:Moderate fertilization levels are required. Fertilize the crop weekly with 100 -150 ppm nitrogen (at 2 kg/m³ slow release fertilizer in substrate), using a complete balanced fertilizer. Avoid high ammonium and high nitrogen levels. Avoid pH above 6.0, as high pH causes iron deficiency. Apply chelated iron, if chlorosis becomes a problem. To prevent magnesium deficiency apply magnesium sulphate (0,025 %) 1-2 times.
* 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.