As John Innes Composts have been used by growers and gardeners for over 50 years, they have clearly stood the test of time, and they are still popular for the following reasons:
Loam-based - John Innes Composts are loam-based - a natural medium for growing plants. Loam contains clay, humus and trace elements which provide a natural reserve of plant foods and also an excellent buffering capacity - so that it can cope with some degree of over- or under-feeding of the plants.
Air/Water Balance - Loam, peat and coarse sand provide a good balance between the amount of water held by the compost and the amount of air space after it has drained. It is easier to achieve this when three main ingredients are utilised, than when the compost is made from only one material such as peat.
Easy to re-wet - The loam and coarse grit content makes a John Innes Compost very easy to re-wet after drying out, compared with all-peat composts.
Natural pH - The pH level of John Innes Composts is at the natural level for most plants, except the lime-hating varieties such as Azaleas, Heathers and Rhododendrons.
Higher Nutrient Levels - Because of the loam content in John Innes Composts, the fertiliser levels can be increased to suit the vigour or growth rate of the plant, which would not be safe in peat-based composts.
Longer Lasting - John Innes Composts last for a longer time than soil-less composts before it becomes necessary to water and feed plants in pots or containers.
Greater Tolerance - With both short and long term fertiliser release, natural drainage and water retention, a John Innes Composts has greater tolerance and gives the amateur gardener better all round results than soil-less composts.
In conclusion, John Innes composts mean easier management and better plant growth particularly for:
Bedding plants and vegetable seedlings
Tomatoes, cucumbers, and melons
House plants and interior planters
Tubs, troughs, patio planters and window boxes