Composts from distillery wastes as peat substitutes for transplant production

The use of composts from distillery wastes as alternative growing media ingredients for transplant production instead of peat, whose harvesting constitutes a severe environmental damage, was studied. Two composts were prepared with exhausted grape marc and cattle manure (C1), and with exhausted grape marc and poultry manure (C2). Four vegetable species, lettuce (Lactuca sativa), chard (Beta vulgaris), broccoli (Brassica oleracea) and coriander (Coriandrum sativum) were grown. Nine substrates were compared: limed white peat (control); compost C1; compost C2; and six mixtures containing 25%, 50% and 75% by volume of each compost with the corresponding peat as diluent. The germination and the effects on the transplant morphological and nutritional aspects of the different mixtures peat/compost considered were studied. All media elaborated showed adequate physical, physico-chemical and chemical properties compared to peat for their use as growing media in horticulture, being these two composts suitable ingredients for the partial substitution of peat, in quantities of 25–50% by volume, without causing any loss in the yield and in the results obtained for the nutritional status when compared to those obtained using the control.