2002 OSU OSTEOSPERMUM CULTIVAR TRIAL ~ GREENHOUSE RESULTS ~ by By Monica Kmetz-Gonzalez and Dr. Claudio Pasian Department of Horticulture & Crop Science, The OSU, Columbus, OH Greenhouse trialing of Osteospermum commenced at OSU in 1998. This past trial involved the screening of 31 cultivars. Plants are generally grown under the recommended cultural conditions, with the exception that no growth regulators are used. This provides the data on plant height, days to flowering, etc. that occur naturally in each cultivar. More than one third of the cultivars screened in 2002 were experimentals, so this data is extremely valuable. Procedure. Rooted cuttings of 29 cultivars from the Paul Ecke Ranch (Encinitas, CA) and 2 cultivars from the Henry F. Michell Company (King of Prussia, PA) were received on January 9, 2002. The following cultural schedule was observed: 1/9/02, Week 0 Rooted cuttings received. Transplanted to 4.5" pots. Potting  Media: MetroMix 360. Greenhouse Temperature: 72F day/night 2/6/02, Week 4 Pinched plants to 5 - 6 nodes 2/20/02, Week 6 Cold vernalization initiated: 46F day/night 4/3/02, Week 12 Temperature changed back to warm: 65F Day/ 55F Night 5/6/02 - 5/10/02, Week 18 Majority of cultivars @ peak flowering/ Evaluation performed. Fertilization : 20-10-20 200ppm N ~3x/week initially. Changed to Greencare 17-5-17 150ppm N on 3/21/02; Back to 20-10-20 200 ppm N on 4/5/02. Conditions. A few cultural problems were encountered during the trial period. 1) Beginning in late February, some mottling was noted on the older leaves of approximately half of the cultivars, suspected to be caused by iron toxicity due to lower pH. Fertilizer was changed to Greencare 17-5-17 for a period of time, and the problem stabilized. Eventual flowering and flower quality did not appear to be affected. 2) At the end of March, some Botrytis was noted on 6 plants. Plants were being grown on capillary mats, and the resultant humid conditions helped promote the disease. Plants were promptly treated with Phyton 21, and the spread of the disease was halted. Ratings and Results. Initially, 15 plants per cultivar were transplanted. Some of the experimentals had less number of plants. For the evaluation itself, 10 plants per cultivar were given an overall aesthetic rating on a 1 to 5 scale, with 1 = poor, and 5 = excellent (Table 1) . The ratings were performed by a 7 person team comprised of the trial coordinator and staff and Master Gardener volunteers. The trial coordinator also recorded data at the time of evaluation on plant height to foliage, plant height to flower, days to 1st flower, and days to peak flower. These results are presented in (Table 2) . The plants once again provided a beautiful visual display in the greenhouse at time of peak flower. Three of the top 5 finishers were experimental lines, which definitely will merit further trialing. The top 8 finishers in order were: Cape Daisy ëBeira', Exp. #1051-199, Side Series ëSeaside', Exp. # 200039, Exp. #200024, Cape Daisy ëVolta', Cape Daisy ëOrania Peach', and Sunny ëSonja'. All of the cultivars were planted outdoors as part of our Summer Garden Trials. Results from that trial can be found in a separate report. Take a view of the trial: (Photo 1) (Photo 2) (Photo 3) Acknowledgements. Appreciation goes to Departmental staff members David Snodgrass and Marcia Feller for their assistance. We would also like to acknowledge, and give a huge thanks to our team of Master Gardeners. Sources of Plants: Paul Ecke Ranch, Encinitas, CA Henry F. Michell Company, King of Prussia, PA