There are different types of growing media, each one of them suitable for a special job. You will achieve a higher success rate if you will use the right compost for each job. There are three major types of growing media that you can find on the market: standard seed compost, standard cuttings compost and inert growing media.
Standard seeds compost
Seeds, especially the fine ones, need good contact with compost to germinate. They should be sown in purpose-made seed compost, which is fine-textured, moisture-retentive and low in nutrients, as salts found in very nutritious compost may damage the seedlings. The standard seeds compost is made by two parts sterilized loam, one part peat substitute or peat and one part sand. To this mixture, for each cubic meter of volume is added 1.2 kg superphosphate of lime and 600 g ground limestone.
Standard cuttings compost
Cuttings need free-draining compost which is intended for use in high-humidity environments, as cuttings need humid conditions in order to root. The compost used for cuttings may be based on bark, perlite or mixtures containing a high percentage of coarse sand. Like seeds compost, cuttings compost is low in nutrients, so once the cuttings have rooted they need feeding. A standard cutting compost found on the market typically contains half sand and half peat substitute or peat. To this mixture, for each cubic meter is added 4.4 kg dolomitic lime, 1.5 kg hoof and horn or dried blood, 1.5 kg superphosphate of lime, 1.5 kg calcium carbonate, 150 g potassium nitrate and 150 g potassium sulphate. At the end, a specialist micro-nutrient fertilizer is added to the mixture.
Inert growing media
For more sensitive seeds or cuttings, this sterile material is good because it does not harbor the potential pest and disease problems associated with soil-based or loamless potting compost. The most common inert growing medias found on the market are: rockwool, perlite, vermiculite and clay granules. Clay granules are also used for hydroculture.
