The use of composted hazelnut husk (CHH) as a plant growth medium was investigated. The mediums were prepared using different fractions of CHH mixed, in different ratios, with clay loam soil. Firstly, an aggregate size distribution of CHH was performed so that a series of different fractions were determined: 0-2 mm, 2-4 mm and 4-6.35 mm. These CHH fractions were then mixed with soil in quantities of 2%, 4% and 8%. Some of the physical and chemical properties of the growing medium were then determined. CHH material showed different properties according to fraction size. All sizes of composted hazelnut husk fraction affected soil properties. The 8% mixture of course fractions (2-4 mm and 4-6.35 mm) had the greatest effect on physical soil features, the 8% mixture of smaller fractions (0-2 mm and 2-4 mm) had the greatest effect on soil chemical properties. The mixture of the 2-4 mm fraction size and the 8% mixture was found to offer the most ideal growing media properties because of the affect of the 2-4 mm fraction size of composted hazelnut husk on all of its properties.