RESPONSE OF NEW GUINEA IMPATIENS TO FERTILITY LEVEL IS AFFECTED BY APPLICATION FREQUENCY
New Guinea impatiens (Impatiens sp. hybrids) are particularly sensitive to growth medium soluble salts level during the first four to six weeks after potting. Results of this experiment show that this response is affected by the interaction of fertilizer rate and application frequency. Solutions containing 20N-4.3P-16.6K at 0.5, 1.0, 1.5, or 2.0 g·liter-1 were applied to `Selenia' growing in 520 ml pots 4, 8, 12, or 16 times (evenly-spaced) during a 70 day experiment. A significant interaction occurred between fertilizer rate and application frequency. Shoot dry weight (DW) increased linearly with application frequency at 0.5 g·liter-1. Overall 16 applications of 0.5 g· liter-1 resulted in the most growth of all rate and frequency combinations. Maximum DW at 1.0 g·liter-1 was achieved with 12 applications and 8 applications resulted in the most DW with 1.5 and 2.0 g·liter-1. In treatments where growth was inhibited, growth medium EC exceeded 1.0 dS·m-1. EC did not exceed 0.4 dS·m-1 at any application frequency with 0.5 g·liter-1.