Physical analysis of rockwool slabs and effects of fiber orientation,irrigation frequency and propagation technique on chrysanthemum production 1

Chrysanthemum X morifolium ’Bright Yellow May Shoesmith’ was grown as a cut flower crop in rockwool slabs in various methods to test different cultural and rockwool options. Direct planting of unrooted and calloused cuttings led to deleterious water stresses in spite of a commercially prohibitive input of labor for syringing. Planting of partially rooted cuttings was successful in terms of flower production but required excessive labor. Satisfactory and equal results were obtained from 1) inserting cuttings rooted in rockwool cubes into the slab such that the cube top was either flush or 1.3 cm above the slab surface, 2) applying nutrients 1 or 3 times per day, and 3) a horizontal or verticle fiber orientation in the slab. Nutrient accumulation in plants of all treatments were in satisfactory ranges and did not account for observed differences in growth.