Culture Options
A. Pot Culture
Because spray chrysanthemums in pots are so flexible and reliable, they serve as an excellent way to grow spray mums for small and medium-size growers. They can be grown to target major cut flower holidays, such as Valentine’s Day, Easter, Mothers Day or Thanksgiving. They offer potential use as a rotation for summer in greenhouses equipped with blackcloth systems that may not be fully utilized due to the slower summer sales period for potted plants. And, of course, pot culture lends itself to crops grown on weekly or biweekly rotations throughout the year.
Three plants per 6” pot or 4 plants per 7” pot are recommended for single-stem culture. Normally 6” pots would be spaced 8” x 8” to 8” x 9’. Spacing for 7” pots would be approximately 9’ x 9” to 9” x 10”.
Spray chrysanthemum pots should be filled with moist root media. Plants should be fertilized and watered as soon as they are planted. Normal schedules are used. Pots can be pot tight or slightly spaced in the long-day or starting area.
B. Single-Stem Crops
The majority of spray mums in North America and, indeed, the world are produced as single-stem plants. The cuttings are planted, provided with the appropriate number of “long days,” followed by “short days” and allowed to flower. Other than preparing the beds or pots and planting the cuttings, little labor is needed until harvesting.
Single-stem crops require no pinching and no pruning of lateral branches. Single-stem crops require less crop time and typically produce heavier stems and more flowers per stem than pinched crops. Disbudded spray mums are almost always grown as single-stem plants in order to (1) reduce crop time and (2) achieve maximum flower size and quality.
C. Pinched Crops
Under high light, summer-like conditions, some growers take advantage of the environment and produce pinched crops. With proper spacing, pinching and pruning, good quality stems can be produced from pinched plants.
Proper pinching of spray mums provides strong, uniform branching and helps to provide the terminal-type spray formation desired by most growers and users of spray mums.
Published schedules suggest that sprays be pinched 2 weeks after planting in the summer and 3 weeks after planting in the winter. This allows time for development of new soft growth prior to the pinch. Remove the top 1/2” to 1” of tip growth. Pinching into hard wood will restrict both the number of breaks and growth potential.
After the new breaks have developed, many growers will prune back to a set number of breaks per plant to help control the finished quality. An example of this would be to leave 3 stems on the outside row and 2 stems on all plants in the interior of the bed. The more stems per plant you attempt to flower, the more uneven the flowering and the more thin stems you will produce.
D. Natural Season Crops
Natural season crops follow the lead of nature; no photoperiod control is needed. They are planted in July and August under warm temperatures and high light conditions. They will flower in October and November under lower light and cooler temperatures. Growth occurs under intermediate, changing levels of light and temperature.
Generally light levels during the natural season are high enough to allow pinched crop culture. (However, higher quality stems are produced with single-stem culture.) Typically, plants are pinched 2 weeks after planting.