SCHEDULING OF GLADIOLUS, CELOSIA, HELIANTHUS, AND ZINNIA

Starting at the beginning of April, four plantings of Celosia argentea var. cristata L., Helianthus annuus L., Zinnia elegans Jacq. in 3-week intervals and starting at the end of February, plantings of Gladiolus x hortulanus L. H. Bailey in 2-week intervals were conducted to determine certain characteristics of these cut flowers. Days to flower bud, flower formation and harvest were recorded on all crops for each scheduled planting. Days to bud decreased for Gladiolus and Helianthus in warmer temperatures and longer daylengths, while days from bud to harvest were less for Celosia and Zinnia for later planting dates, warmer temperatures and longer daylengths. Postharvest longevity differences between pollen-producing and pollenless varieties of Helianthus were determined on stems stored in a simulated interior environment. Nonpollen producing varieties were of acceptable quality an average of 1 to 3 days longer than pollen-producing varieties. The number of days of acceptable quality was determined by visual observation of the first signs of petal wilt, drop, or curl. Zinnias were harvested by two different cut stem lengths, 31 cm and 46 cm, to determine yield differences. Plants with stems cut at 46 cm yielded an average of 30% fewer flowers than those cut at 31 cm. The first planting of Helianthus and Gladiolus had the best quality and highest yield, while the second planting of Zinnia and the forth of Celosia resulted in higher quality and greater yields.

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