For final potting of plants into pots or outdoor containers. Levington John Innes No.3 compost has the highest nutrient levels for final potting of mature plants, patio planters and for the final potting of tomatoes and other vegetables.What is John Innes compost?John Innes compost is predominantly peat based but also includes sterilised loam and has a higher proportion of heavy particles like grit and sand than other composts and as a result is much heavier. A numbering system is used to indicate the nutrient levels within the compost.