Culture Report: Dianthus Corona Series By Reid Snyder

Add a regal touch to cool-season sales.

Expanding your sales for cool-season and seasonal programs is an important strategy for better profits and to meet your customers’ needs for early sales in the garden center. Offering an option with maximum shopper appeal is a bonus! The new Corona dianthus series from PanAmerican Seed is an upgrade to traditional D. chinensis. Corona has huge flower power with the largest blooms of any dianthus of this type on the market.

In addition to its big impact, Corona displays an exceptional flower form in a palette of show-stopping color choices: Cherry Red, Rose, Strawberry and White. It is also a versatile plant that thrives in cool-season landscapes, gardens and patio planters, adding a regal touch anywhere it is planted — especially mixed with other cool-weather plants, such as pansies.

The series exhibits uniform flowering time and habit. It generates multiple flowers on a compact, mounded plant. To produce this attractive new series in your greenhouse, follow the guidelines to the right.


Corona is offered as pelleted seed. Germination takes three to five days at 64 to 68° F. Light is not required to germinate, but can be beneficial. Cover the seed with a medium layer of coarse-grade vermiculite after sowing to maintain uniform moisture around the seed during germination.

Use a media with an initial pH of 5.8 to 6.2 and EC of 0.75. To control hypocotyl stretch, especially when grown under DLI lower than 5 mol∙m-2∙d-1 conditions, a paclobutrazol 5-ppm spray at radical emergent stage can be used.

During Stage 2, provide moisture levels of 3 to 4 (medium to medium-wet) with temperatures at 65 to 70° F. DLI about 5 to 8 mol∙m-2∙d-1. Apply a fertilizer less than 100-ppm nitrogen and less than 0.7 EC. If necessary, apply a paclobutrazol spray at 5 ppm.

Temperature and moisture requirements drop slightly in Stage 3 to 60 to 65° F and moisture at level 2 to 3 (dry to medium). Raise light to 8 to 10 mol∙m-2∙d-1. Another paclobutrazol 5-ppm spray provides adequate plant growth regulation for attaining Corona’s compact habit.

During toning stage, lower temperatures to 55 to 60° F but maintain high light levels again at 10 mol∙m-2∙d-1.


Corona is a facultative long day crop; it will flower slightly faster (five to seven days) under daylength of 14 hours or longer. It prefers to be grown under high light intensity and cool nights. Under low DLI, crop time will be delayed.

Day temperatures should be set between 60 to 72° F. Keep night temperatures between 50 to 60°F. The target media pH should be 5.8 to 6.2 and EC 1.5 to 2.0. Feed Corona with 175- to 225-ppm nitrogen; maintain 1.2 to 1.5 EC. A 10- to 15-ppm paclobutrazol spray is recommended for height control a couple weeks after transplant.

Reid Snyder

Reid Snyder is global production manager for PanAmerican Seed and stationed at its Santa Paula, California, facilities. For full culture details, visit