John Innes refers to the compost type and is not a compost manufacturer. The range of John Innes composts were originally developed in the 1930’s at the John Innes Horticultural Research Institute, named after the 19th century developer and philanthropist, John Innes, who bequeathed his fortune to the improvement of horticulture.
The John Innes ingredients that he originally mixed together became a well known and trusted recipe amongst horticulturalists and growers. Many gardeners and growers today trust the John Innes blends to get them better growing results.
John Innes composts weigh much more than other types of potting compost because the key ingredient is loam, or soil, along with peat or peat substitute, sand, and fertiliser. A compost that states that it is a John Innes compost must contain Peat.
The key added ingredients in a compost that comes with ‘added John Innes’, are loam, a source of fertiliser N:P:K, and some sand. A compost that is Peat-Free can come with ‘added John Innes’. RocketGro composts that come with ‘added John Innes’ derive their N:P:K naturally from one of the core substrates in our composts; Digestate. This enables RocketGro to stay true to their chemical free Organic values.
John Innes No 1 is designed for pricking out or potting on young seedlings or rooted cuttings. It contains a low, carefully balanced amount of fertiliser to give enough for growth but avoid scorching the delicate young roots.
John Innes No 2 contains moderate levels of fertiliser and is used for potting on plants at the next stage of growth, and most vegetables.
John Innes No 3 contains the highest levels of fertiliser and is suitable for mature plants growing in pots, such as shrubs, small trees, perennials, and conifers.