2 PhotoperiodismThe response of different periods of day and night in terms of plant growth and maturityLong day plants flower when days are long and nights are shortShort day plants flower when days are short and nights are longChrysanthemumsPoinsettias
4 Chrysanthemums Most popular cut flower sold in the U.S. Popular as a potted plant for Mother’s Day, Memorial Day, and EasterSecond only to poinsettias in dollar value for potted flowersMany different cultivars are grown
5 Planting Chrysanthemums Rooted cuttings are available from wholesale growersThe number of plants to use depends on the pot size4” pot has 2 plants5” pot has 4 plants6” pot has 5 plants
6 Chrysanthemum Temperatures During the first two weeksGreenhouse temperature should be 63 degrees F at night and on cloudy daysOn sunny days the temperature should be 70 degrees F
7 Chrysanthemum Temperatures After the first two weeksGreenhouse temperature should be kept at 62 degrees F at night and on cloudy daysOn sunny days temperature should be kept at 70 degrees F
8 Chrysanthemum Temperatures During the last three weeksGreenhouse temperatures should be kept at 55 degrees at night and on cloudy daysOn sunny days greenhouse temperatures should be kept at 65 degreesUneven bud set is caused by improper temperatures
9 Pinching Chrysanthemums Pinching is done to make a more compact plant with more flowersDisbudding is done to control or reduce the number of flowers per plant
10 Media and Fertilization Media must be free of diseases and insectsSoil must be porous and well drainedRegular fertilization should be done with a liquid fertilizer at 250 ppm at each watering
11 Chrysanthemum Photoperiod Short-day plantBud set light period is 14 ½ hours or less of light, and flower development takes place when daylight is 13 ½ hours or lessVegetative growth takes place when light period is less than 12 ½ hours
12 Chrysanthemum Photoperiod From August to May 15, light is used during the middle of the night to break the long dark periodsFrom March 15-October 20, black cloth is used to give about 12 hours of darkness from about 5 p.m. to 7 a.m.
14 Poinsettias Most important pot plant grown for the Christmas season Many different cultivars are grown
15 Planting Poinsettias Wholesale growers supply 2 ¼” rooted cuttings Number of plants per pot depends on pot size, whether plants will be pinched or grown as a single stem, and size of flower4” pot has 1 plant for pinched or for single stem6” pot has 2 plants for pinched or 3-4 for single stem8” pot has 3-4 plants for pinched and 6-7 for single stem
16 Poinsettia Temperatures Greenhouse temperatures should be 65 degrees F at night and degrees F during the daySome cultivars vary slightlyIf night temperatures get above 80 degrees F, flowering will be delayed or may not flower at all
17 Pinching PoinsettiasPinching may be done to increase the number of bracts on the plant and to make the plants appear fuller.
18 Media and Fertilization Media must be free from insects and diseases.Soil must be porous and well-drainedLarge amounts of fertilizer are needed from propagation until sold.
19 Poinsettia Photoperiod Short-day plantBud set light period is from 12 hours to 12 hours, 15 minutesVegetative growth light period is longer than 12 hoursTwo hours of light from about 11 p.m. to 1 a.m. each night will cause short day effect