RELATIONS BETWEEN PHYSICAL AND CHEMICAL PROPERTIES OF THE SUBSTRATE AND GROWTH OF SOME POT ORNAMENTALS
It is therefore interesting to research and use cheaper domestic components for the substrates, to replace peat at least partially.
Ten substrates were used on four pot ornamentals of great commercial importance: Ficus benjamina 'Exotica', New Guinea impatiens, F1-cyclamen and pot chrysanthemum.
In the substrates, alternative materials such as a conifer-bark compost, rice husks and pumice were employed.
At the same time, these substrates were analyzed to verify:
- the physical properties more suitable for the best growth of the four tested species;
- the absorption of mineral nutrients from the same species.
The substrates with higher water retention capacity, which peat prevails in, were the best for vegetative plant growth, while better results for flower number and advanced flowering were obtained with the mixtures containing bark compost + peat + draining component in the proportion of 3:2:1; the only exception was New Guinea impatiens, that requires high water availability in the substrate.
Among the draining components, rice husks and pumice, which are much cheaper than perlite, gave the same performances as the last one.
The results of these trials are encouraging for the research of alternative substrates: in fact, as regards cyclamen and pot chrysanthemum, the best cultural results were achieved by reducing the quantity of peat in the substrate to 1/3 of the total amount.