ISHS Acta Horticulturae 614: VI International Symposium on Protected Cultivation in Mild Winter Climate: Product and Process Innovation
GROWTH AND FLOWERING OF GERANIUM AND NEW GUINEA IMPATIENS IN PEAT-REDUCED AND IN PEAT-FREE SUBSTRATES WATERED WITH DIFFERENT IRRIGATION SYSTEMS |
| Authors: | A. Pozzi, P. Frangi, M. Castelnuovo, A. Pardossi |
| Keywords: | coir dust, drip, ebb/flow, Impatiens hawkeri, Pelargonium x hortorum, polyurethane |
| Abstract:
In order to investigate possible alternatives to peat, plants of zonal geranium (Pelargonium x hortorum Bailey, cv. Praeludium) and New Guinea impatiens (Impatiens hawkeri Bull., cv. Riviera Red) were cultivated in four different substrates containing coir dust or polyurethane in combination with peat and perlite, while a reference substrate (T) was composed by a mixture of peat and perlite. Each substrate was watered by means of ebb/flow or drip irrigation. Fertigation frequency was regulated by tensiometers. For both species, plants grown in substrates containing 30% (C1) or 50% (C2) of coir dust had a development similar to or even higher than the one reached in T. New Guinea impatiens grown in C1 and C2 substrates showed the same ornamental value as in T substrate, regardless of the irrigation system, while in geranium C2 substrate gave rise to lower quality plants in ebb/flow system in comparison with C1 and T substrates. The substitution of peat with polyurethane had a negative effect on plant growth and quality in both the species, especially with ebb/flow system. Symptoms of marginal necrosis of leaves, due to an excess of Zn, were observed in New Guinea impatiens when polyurethane was added to the substrate. | |
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