The effect of rockwool on physical properties of growing substrates for perennials

Abstract

The possibility of peat replacement with crushed water absorbent rockwool in growing substrates in the amount of 35% vol. was verified in the experiment with perennials in containers. Three types of substrates, i.e. peat, and two mixtures of peat with alternative components - green waste compost (25% vol.) or composted spruce bark (40% vol.) were compared. A sand box in the range of -0.5 to -10 kPa was used to determine retention curves and other physical properties of the components and substrates. The addition of rockwool to the peat substrate increased content of air and easy available water, the plant growth was not affected. Plants grown in substrates with alternative organic components were smaller in comparison to peat substrate. The growth of perennials significantly decreased, mainly in substrates with bark, but the plants had good market value. The addition of rockwool to these substrates had no significant effect on the growth. Crushed rockwool in the amount of 35% vol. can replace peat in peat substrates and in mixtures with alternative components.