John Innes composts

Abstract

The John Innes composts were developed as a result of investigations by Lawrence & Newell (1939), at the John Innes Horticultural Institution, into the high mortality rate of Primula sinensis seedlings being raised for genetical studies. This work was the first attempt by researchers to produce a standardized medium, suitable for a wide range of plants. Prior to this, there had been no standardization of materials or compost formulae; growers prepared individual mixtures for each species of plant from carefully preserved and guarded recipes. In addition to the well-rotted turf loam, chopped with a spade into walnut size pieces, which formed the basis of the composts, a wide range of other materials was used, including mortar rubble, crushed brick, burnt clay, charcoal, well-rotted animal manure, spent hops, leaf mould, etc., and fertilizers such as bone meal, steamed bone flour, flue dust, bonfire ashes, etc.