Garden mums - Early season
Monday, 24 May 2010 13:55
Mum cuttings are arriving at some growers. Begin the season by reviewing your fertilizer program and teaching new employees to recognize Chrysanthemum white rust symptoms.
Mums are heavy feeders during the first few weeks. Growers use a variety of ways to fertilize mums. Some growers use 100% water soluble fertilizer through a drip system, some use 100% controlled-release fertilizer and some use a combination of water soluble and controlled-release. Regardless of the program you use, start plants off right and prevent premature buds by:
Using moistened soil when potting up plants, then water-in freshly planted cuttings with a fertilizer solution. Many growers are successfully using 200 to 300 ppm of 20-20-20 immediately after planting. The cuttings establish faster and grow more rapidly.
Do not stress the young plants during their first 4 to 5 weeks of growth, and especially during the first 10 days of the crop or plants will develop buds prematurely and plants will be short. Keep plants moist, well fertilized and properly spaced.
Also check plant roots regularly to monitor plant health.
To encourage soft growth that branches freely, many growers use 250-300 ppm 20-20-20 or a fertilizer that is at least 60% ammonical nitrogen as a constant feed during the first 2-3 weeks for all fertilizer programs. Then, growers using 100% water soluble fertilizer throughout the season, switch to 200-250 ppm 20-10-20 constant feed for 3-4 applications and then rotate to a calcium nitrate based fertilizer such as 15-0-15 for 1 application, then repeat. The 20-10-20 contains less ammonical nitrogen. Once plants start to show color, fertilizer is reduced to 100 ppm constant feed.
If using controlled-release fertilizer, keep in mind that the rate of release is affected by its formulation (rate of release), soil temperature and frequency of irrigation. Most formulations release at temperatures of 70°F or above, therefore during cool temperatures, fertilizer is going to be slow to release. We often have cool temperatures in June when plants need the most fertilizer. This is the reason liquid feed becomes important, to get plants growing and create vegetative growth.
Garden mums initiate flower buds easily and develop rapidly if plants are stressed in any way. If terminal flower buds are observed when cuttings arrive, plants should still perform satisfactorily. When cuttings with terminal flower buds are planted, they should be pinched hard (allow 4-5 leaves to remain) when they are turgid (4-5 days after planting). This will force out lower breaks which tend to be more vegetative. If both terminal and lateral buds have developed when cuttings arrive, it is best not to plant them, as they most likely will not perform satisfactorily.
Tina Smith, University of Massachusetts
For more information see:
Fact Sheet: Garden Mums for Fall
Fact Sheet 2008: Chrysanthemum White Rust.
Grolink: Belgian Mum Cultural Information
Fact Sheet. Garden Mums from Cell Paks. Griffin Greenhouse Supply Company.
