Growth and nutrition of geraniums grown in media developed from waste tire components

Abstract

Two cultivars of zonal geraniums (Pelargonium xhortorum Bailey), 'Danielle' and 'Kim', were grown in media containing three grind sizes of rubber (2.4, 6, or 10 mm) and fiber from the fabric belting processed from waste tires in three proportions: 1 rubber or fiber: 1 peat; 1 rubber or fiber: 1 vermiculite: 2 peat; and 2 rubber or fiber: 1 vermiculite: 1 peat (by volume). Two control media were also included: 1 vermiculite: 1 peat, and 1 rockwool: 1 peat (by volume). Geranium plants were grown in media containing up to 25% waste tire products along with traditional medium components without reducing plant quality. Plant growth was best and flower count was highest in the vermiculite and peat medium, plants were smallest and flower count was lowest in media containing the rubber grinds at 2.4 or 6 mm, making up 50% of the media. The medium 1 rubber : 1 vermiculite: 2 peat, regardless of grind or fiber, produced plants equal to the rockwool and peat moss medium. All plants grown in media containing rubber by-products had elevated Zn and Cu in the foliage; however, Zn and Cu were highest in media containing 50 % rubber. Foliar P: Zn ratios were less for plants grown in media containing 50% rubber and also were lower in plants grown in media with smaller rubber grind sizes.