PRODUCTION AND POSTPRODUCTION PERFORMANCE OF 2 NEW-GUINEA IMPATIENS CULTIVARS GROWN WITH CONTROLLED-RELEASE FERTILIZER AND NO LEACHING

The objectives of this study were to determine 1) the minimum controll ed-release fertilizer (CRF) rate and the lowest constant medium moistu re required to produce the highest quality plants and 2) if this produ ction system affected quality of these plants under two postproduction light levels, Two New Guinea impatiens (Impatiens sp, hybrids) 'Illus ion' and 'Blazon' (Lasting Impressions Series) differing in salt toler ance were groan for 42 days with a CRF at three rates (3.3, 6.6, or 9. 9 g/pot) and two medium moisture levels (low or high) without leaching , The high moisture level (tension setpoints of 1 to 3 kPa) and 6.6 g of CRF/pot produced optimum biomass. Low medium moisture (tension setp oints of 4 to 6 kPa) reduced leaf area,leaf number, leaf N content, ro ot, stem, and leaf dry masses as CRF rate increased from low to high f or 'Illusion', Similar results in 'Blazon' were observed as CRF rates increased from 3.3 to 6.6 g. Biomass decreased no further at the high rate of 9.9 g/pot, Biomass increased in both cultivars under high medi um moisture when CRP rates increased from 3.3 to 6.6 g, Biomass of 'Il lusion' decreased at 9.9 g/pot, although no symptoms of salt sensitivi ty were observed (i.e., leaf tip burn). 'Blazon' maintained a similar biomass when amended with 9.9 or 6.6 g CRF/pot, although electrical co nductivity (EC) in the medium was 5.9 dS . m(-1) in the upper half and 4.1 dS . m(-1) in the lower half of the medium at the end of producti on. Growth of 'Illusion' responded more favorably to postproduction li ght levels that were similar to those of production regardless of trea tment imposed during production, Similar biomass responses occurred fo r 'Blazon' regardless of the postproduction light level.