GARDEN ADVICE
Getting to Grips with Growing Media
There is a vast array of growing media available to the amateur gardener these days. So here is a basic guide to what's what in the compost world.
John Innes composts are based on loam. They were developed as a result of the work done at the John Innes Institute in the 1930s. They come in several formulations for specific purposes such as seed sowing, pricking out (No 1) and re potting (Nos 2 and 3).
Loam based composts tend to have better water retaining attributes and to re wet more easily than peat based composts. Loam is a fairly heavy material and it is particularly useful in containers where the pot needs to be stable enough to copy with a tall plant or specimen plant without toppling over in high winds.
Multi-Purpose compost speaks for itself. It can be used for seeds although I prefer to use seed compost which is more suited to the growth and low nutrient requirements of seedlings. I find it very useful for potting on, planting up hanging baskets and containers and for use at the bottom of the planting hole when planting shrubs in the garden. Multi-purpose is ideal for the gardener who does not wish to buy several types of compost for particular tasks. A newer concept is multi-purpose compost with added John Innes and "Plant and Gro" compost. As the name suggests it is a multi-purpose compost which is enriched with plant food. This means that rather than needing to feed approximately six weeks after planting the food content should be sufficient for eight weeks or so.
There is also a proliferation of compost for specific purposes such as tub and basket compost which contains a high potash feed (to encourage flowering) and water retaining gel. It also has a more open structure to help watering.
Over the last few years major strides have been made in the development of Peat Free composts which are usually made from organic recycled materials. There are even peat free growing bags now available. There were teething problems when the first peat free products came onto the market but recently there has been significant improvement.
Ericaceous compost is a must for plants which hate lime such as Rhododendrons, Azaleas, Camellias, Acers and some Heathers which would struggle severely in ordinary compost.
