Container Medium and Slow-release Nitrogen Fertilizer Influence Growth and Quality of Salvia farinacea

Abstract

We examined responses of Salvia farinacea Benth. (mealy blue sage, a water- and nutrient-efficient native landscape plant for the southern United States) to slow-release (8- to 9-month), resin-coated urea (39N-0P4K) preplant-incorporated at 0.5, 1, 2, or 3 kg N/m 3 in 2 perlite: 1 vermiculite (PV) or 2 pine bark: 1 fine sand (BS) (both by volume). This slow-release fertilization was compared to weekly fertigation at 100 mg N/liter from ammonium nitrate (34N-0P4K). After 21 weeks of greenhouse culture in 3.8-liter containers, shoot dry weight was higher in BS than PV when these media received fertigation or contained slow-release fertilizer at 21 kg N/m 3 . Shoot dry weight and shoot quality were not increased by exceeding 1 kg N/m 3 in PV or 2 kg N/m 3 in BS. Fertigation resulted in shoot dry weight and shoot quality equal to the highest values achieved with slow-release fertilizer. Cate-Nelson analysis showed that shoot N concentration should be ≥ 4.0% for this element not to limit plant growth.