The 2009 ASHS Annual Conference

Controlled release fertilizers (CRF) in production systems have been known to reduce environmental contamination. However, there is a lot to be explored as per its use in bedding plant production. There is little information about CRF use and their possible post-production (retail or consumer phase) benefit in bedding plant production. The objective of this study was to evaluate the carryon effect (post-production in the field) of CRF on the field performance of bedding plants. Plants were treated with Osmocote Plus 16-9-12 (16N-4P-10K) of 5-6 month longevity (5-6M), 8-9 month longevity (8-9M), or a blend of both CRF (50% each), and 150 mg·L^-1N of 20-10-20 (20N-4.4P-16.6K) water-soluble fertilizer (WSF). The plants were grown for 54 days in the greenhouse where some of the plants from each treatment were harvested and shoot dry weight determined. The remaining plants were transplanted in the field and left to grow for 73 days, after which shoot dry weight was determined. During the study, flower number, flower dry weight, plant quality and leaf yellowing were evaluated. CRF treated plants with 5-6M produced the least shoot dry weight in the greenhouse compared to those treated with 8-9M or WSF. There was no significant difference in the shoot dry weight of plants from all treatments after growth in the field. However, CRF treated plants produced less flower dry weight in the field. Based on plant dry weight, CRF does not have a post-production benefit on the performance of I. wallerana. However, consumers preferred CRF treated plants in the field as compared to WSF treated plants. CRF treated plants were more compact and robust with less leaf yellowing as compared to WSF treated plants. The compactness of the CRF treated plants may be associated with the lower amount of phosphorus in the plant tissue. The ultimate purchasing decision by a consumer depends on the aesthetic value of the plant rather on its weight. This experiment demonstrated that CRF has a positive effect on consumer preference yet no effect on the dry weight of Impatiens wallerana.