There are a variety of ways to produce garden mums using different pinching and planting strategies. Traditional garden mum production schedules involve planting the end of May or early June and pinching plants two times. The first pinch is given within two weeks of transplanting when roots of the cutting reach the bottom and sides of the container and the tops show 1.5-to 2.0 inches of new growth. The second pinch is given when the axillary shoots from the first pinch are 3 to 4 inches long, usually three weeks later in late June or early July, but prior to July 20th.
New varieties have been bred to branch naturally and produce many branches at flowering. As a result, other production schedules for later crops have been developed include planting later and using a single pinch or no pinch for actively growing plants. Also, for convenience, some growers are providing a single pinch to their rooted cuttings when plants are still in the plug trays instead of after transplanting.
If no pinch is new to you, trial it on a small scale, before devoting the entire crop to this growing method. This technique is only successful if planting actively growing cuttings and the young plants are watered and fertilized for active growth, especially during the first few weeks of production. It is important to prevent plants from becoming water stressed which results in hardened growth, fewer breaks and/or premature flower budding. Use the no pinch method on those cultivars that have been bred to do well when grown this way.
Chrysanthemums are short-day plants. Both flower initiation and development of the flower buds occur more rapidly under short days than long days. However, temperature has a greater influence than day-length on flowering of garden mums. In June, with several cool nights in a row, garden mums can initiate buds prematurely which results in early flowering on short plants. If premature terminal budding occurs, buds can be pinched off, and adequate water and additional fertilizer supplied to allow plants to grow larger and flower later. Some growers leave the buds on the plants and fertilize heavy with the expectation that the vegetative growth will by-pass the budded growth. The plants often continue to grow and develop into a quality fall crop. In some cases plants become uneven with two-tiered appearance. Growers have reported that the plant response varies according to the variety.
Garden Mums, UMass Extension (with links to guides and resources)
Add Fall Color with No-Pinch Garden Mums, University of New Hampshire Extension
Garden Mum Production for Fall Sales, University of Kentucky
Tina Smith, UMass Extension
reviewed by Leanne Pundt, UConn Extension and Douglas Cox, UMass Stockbridge School of Agriculture