Ca, Mg, And Micronutrient Nutrition and Growth of Pelargonium In Pine Bark Amended With Composted Hardwood Bark

Abstract

Growth and foliar nutrient analysis of Pelargonium X hortorum L. H. Bailey cv. Aurora grown in pine bark (PB) amended with 25%,50%, or 75% composted hardwood bark (HB) were studied with the bark components mixed either before or after composting. For each ratio of PB to HB, fresh PB was mixed with fresh HB before composting, or composted PB or noncomposted PB were mixed with composted HB. Media physical properties and plant growth and foliar nutrient levels were the same when media were mixed before or after composting. Plants had more shoot growth in media containing 25% or 50% HB. Media containing 25% or 50% HB had a stable pH during the study, while pH increased in other media. Plants grown in media containing 75% or more composted HB showed symptoms of Mn toxicity during the first month of growth. Except for Cu, plants grown in media containing composted HB had normal or above normal foliar tissue Ca, Mg, and micronutrient levels.