Horticulture Department lerative Extension Service Purdue University West Lafayette, Indiana 47907 Volume 10, No. 1 Edited by P. Allen Hammer February 1982 CONTENTS PAGE 1981 Poinsettia Trial P. Allen Hammer and Terri Kirk 1 Using STS to Prevent Flower Shattering in Seed Geraniums 7 Roundup Labeled for Greenhouse Use Steve Weller 8 Tour of Van Wingerden's 9 Indiana Flower Grower's Association 12 Grow Show '82 13 The Way I See It P. Allen Hammer 14 Cooperative Extension Work in Agriculture and Home Economics, State of Indiana, Purdue University and U.S.Department of Agriculture Cooperating. H.G.Diesslin, Director, West Lafayette, Ind. Issued in furtherance of the Acts of May Band June 30, 1914. It is the policy of the Cooperative Extension Service of Purdue University that all persons shall have equal opportunity and access to its programs and facilities without regard to race, religion, color, sex or national origin.
1981 Poinsettia Trial1 «P. Allen Hammer and Terri Kirk The 1981 trials were with 8 cultivars as single stem (3 plants/6 inch pot) or branched (1 pinched plant/6 inch pot) plant grown at 60 or 65 F night temperature. The day temperature was 70-75 F. The cuttings were rooted in Oasis root cubes. They were potted in a soil/peat/perlite soil mix in plastic pots. Fertilizer applications of 200 ppm N and K (ammonium nitrate, potassium nitrate) and phosphoric acid (water, ph 6.2) were made at each watering. An application of epsom salt (Magnesium sulfate) at 3 lbs/100 gallons of water was made on October 16. Terraclor was applied 1 week after potting and Lesan applied every 4 weeks. Temik was applied every 4-5 weeks. One tablespoon of 14-14-14 Osmocote was applied to each pot on October 2. Cultivars and production schedules are shown in Tables 1 and 2. Height and weeks to flower are shown in Figures 1, 2, 3, and 4. Night temperature had a much greater effect on the height of the branched plants than the single stem plants. Growing at 60 F night temperature greatly increased the time to flowering and significantly reduced bract size. We still recommend a growing temperature of 65 F for poinsettias. Table 1. Cultivars and codes used in graphs Cultivar Code Gutbier V-14 Pink P-14 Gutbier V-14 Jingle Bells JB Gutbier V-14 Glory G Annette Hegg Dark Red DR Annette Hegg Lady Red L Annette Hegg Brilliant Diamond BD Annette Hegg Hot Pink HP Annette Hegg Top White TW Table 2. Production schedules Operation single s tern branched propagation 8/26 8/12 panned 9/28 9/11 pinched 9/24 lights on 9/11 9/11 lights off 10/6 10/6 Thanks to Paul trials. Ecke Poinsettia for supplying the poinsettia stock for Associate Professor and Research Technician, Dept. of Horticulture, Purdue University, West Lafayette, IN 47907.
-2- Single Stem/3 plants/6 inch pot 40-60 NT -65 NT 16. 12 P O 30 ro H 0) 20 1 3 P-14 L BD HP TW Figure 1. Average height above the pot rim for 8 poinsettia cultivars. Means shown are for 10 pots/cultivar Single Stem/3 plants/6 inch pot u <u o <-\ o U CO 0) 0J P-14 JB DR L BD HP TW Figure 2 Time from the start of short days to pollen for 8 poinsettia cultivars. Means shown are for 10 pots/cultivar.
-3- Branched/1 plant/6 inch pot 4J 00 H w P-14 JB DR BD HP TW Figure 3. Average height above the pot rim for 8 poinsettia cultivars Means shown are for 20 pots/cultivar. Branched/1 plant/6 inch pot 12 11 10 ' u o 9 - Pn O 4J CO a P-14 Figure 4, JB DR BD HP TW Time from start of short days to pollen for 8 poinsettia cultivars. Means shown are for 20 pots/cultivar.
-4- *w Poinsettia Trees We grew two plants of each cultivar as poinsettia trees. The pro duction method was the same as given for the 6 inch pots except they were potted in 3 gallon plastic pots and 2 tablespoons of Osmocote was applied on September 15. Table 3. Production schedule for poinsettia trees. Operation potted 1st pinch lower leaves removed 2nd pinch lights on lights off (short days) Date 5/20 7/31 8/21 9/3 9/16 9/26 The page of photographs shows Brilliant Diamond, Glory and Top White at several stages of production. These were certainly the best of the 8 cultivars in the trials. Glory was the best cultivar as a tree for height, color, form and sturdiness. But remember, it must be grown in warm conditions (minimum 65 F) and it appears to have more root rot problems under poor growing condition. I would certainly try a few trees this next year. They are spectacular! A persian proverb says: The three things which can never be returned a spent arrow a spoken word a lost opportunity.
-5-1st pinch 7/31 1eaves removed 8/21 2nd pinch 9/3 W6**^s Brilliant Diamond Glory Top White L,*
-6- early flowering 11/12 flowering 11/30 Brilliant Diamond Glory Top White
-7- Using STS to Prevent Flower Shattering in Seed Geraniums 1 Shattering is a serious problem in many of the seed geraniums grown as bedding plants. Silver thiosulfate (STS) used as a foliar spray has been shown to prevent much of this shattering. STS at 0.1 ounce of STS concentrate per gallon was applied to the plants until buds showed any color. HOW TO MAKE A STS CONCENTRATE Use eithar (read the label) a) prismatic sodium thiosulfate or b) anhydrous sodium thiosulfate grams 120 80 runoff before the ounces 4 1/2 2 3/4 Dissolve the weighed chemical in 1 pint of deionized water. Then weigh out silver nitrate 20 3/4 Dissolve this in a seperate pint of dionized water. Prepare STS Concentrate by slowly pouring the silver nitrate solution into the sodium thiosulfate solution. Stir rapidly as the solutions are mixed. Some browning of the concentrate solution may occur during mix ing, but this does not matter. The solution should be mixed and stored in glass containers. Store the concentrate in a dark refrigerator. The chemicals can be purchased from chemical supply companies or many photo graphic chemical suppliers. ;au4klu 1 Adapted from Arthur C. Cameron, Michael S. Reid and Gary W. Hickman. 1981. "Using STS to Prevent Flower Shattering in Potted Flowering Plants.- Progress Report." Flower and Nursery Report for Commercial Growers. Fall 1981. University of California. Being up the proverbial creek without a paddle isn't nearly as bad as having the paddle and no boat!