EVALUATION OF ORGANIC, SYNTHETIC AND MINERAL SUBSTRATES FOR HYDROPONICALLY GROWN CUCUMBER

Hydroponic substrates so far have been based primarily on rockwool slabs.
Against this background, investigations were made for the comparative evaluation of other substrate materials.
Various organic, synthetic and mineral substrates – wood shavings, perlite, expanded clay aggregates in containers, recycled polyurethane-ether foam (PUR) slabs and rockwool slabs – were compared in experiments on the water and nutrient supply of cucumber.
PUR and rockwool were also examined for the changes that occurred over two years of use.

Several criteria were applied for substrate evaluation: – physical composition and its change, water consumption and amount of drainwater, nutrient balance, ecological quality and economic efficiency of substrates.

Perlite and the organic substrates were found to be most suitable.
Crop yields were also high in PUR, but water consumption and the amount of drainwater were quite high.
An expanded clay substrate ranked last in the complex evaluation by all criteria.
Further investigations will have to show whether many years of substrate use, differentiated nutrient supply and the inclusion of additional criteria would give a different rank order of the substrates under review.

International Symposium on Growing Media & Plant Nutrition in Horticulture

M. Böhme

cucumber, greenhouse, hydroponics, substrates, nutrient solution, drainwater

https://doi.org/10.17660/ActaHortic.1995.401.25