COMPOSTED VEGETABLE, FRUIT AND GARDEN WASTE AS A SUBSTITUTE FOR PEAT IN CONTAINER-GROWN NURSERY STOCK

The need to recycle waste products, coupled with increased environmental lobbying against peat extraction, has focused attention on the feasibility of substituting composted vegetable, fruit and garden waste, VFG compost, for peat.
To ascertain if substituting VFG compost for peat will change the pH, EC and nutrient levels and the physical properties of the potting media, these parameters were monitored in potting media containing varying proportions of four VFG composts, perlite and peat.
Fertilization was adjusted in accordance with pH, EC and nutrient analysis.
A strong correlation was found between large VFG compost amendments and high pH values; these depressed growth appreciably.
In this experiment, fertilization was unable to adequately control pH.

Physical properties were measured by determining the pF-curve of the potting media during the growing season.
Although in some mixtures these properties were poor at the beginning of the growing season, they improved over time and remained within the recommended range for crop production.
No correlation was found between VFG compost amendments and decrease of the physical quality of the potting media.

VFG compost can be substituted for 15% of the peat in the potting medium, if fertilization is adjusted.
Larger amendments of VFG compost can cause appreciable pH problems.
Coarser VFG compost and anaerobically composted VFG compost seem to be more promising.

International Symposium on Growing Media & Plant Nutrition in Horticulture

A.A. Pronk

pH, calcium carbonate content, EC, nitrogen, air content, easily available water

https://doi.org/10.17660/ActaHortic.1995.401.57