John Innes is an array of composts that were created at the John Innes Institute. They are named after John Innes, who was a 19th-century property and land dealer in London. 

The John Innes composts are mainly used for sowing seeds and rooting cuttings, large seed sowing, pricking out, potting up, final potting and mature plants. The various John Innes composts offer different levels of nutrients to aid growth from initial to the end. The John Innes composts are No. 1, No. 2, and No. 3, and they all have different levels of fertiliser.

What is the difference between John Innes 2 and 3?

The different types of compost from Westland

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Properties of the John Innes Composts

Loam – The most important ingredient and the main body in all the John Innes compost is loam. It supplies nutrition needed by the base of the plant to help absorb and release plant nutrients as required.

Peat – The Sphagnum Moss Peat increases the total porosity and improves both the aeration and the water-retaining capacity. It also decomposes slowly into humus.

Sand – Coarse sand or grit is used as a physical conditioner to allow excess water to drain from the compost which prevents waterlogging. It also provides stability for larger plants.

Fertiliser – The compound fertiliser in John Innes Compost provides a wide spectrum of plant nutrients needed for balanced growth, for example, Nitrogen, Potash etc.

What are John Innes 2 and 3?

John Innes 2

The John Innes No.2 compost is developed specially to help all young plants and ensure healthy root and shoot development. It has an increased level of potassium humate, which is a biostimulant for healthy growth. 

Also, it consists of peat and loam which are great for nutrients, retaining moisture, sand and grit to drain excess moisture. They are used in the general potting of most house plants and vegetable plants into medium size pots or boxes. 

John Innes 3

The John Innes No. 3 compost is a loam-based compost with a naturally reduced peat mix. This compost is more suitable for re-potting or planting mature plants. It is mostly used for heavy feeding vegetables and flowering plants in hanging baskets, large troughs, planters and containers. It aids in prolonging the lifespan of a plant. 

Differences between John Innes No. 2 and No. 3

  1. Types of plants

The John Innes No. 2 compost is used mainly for young plants, house plants and vegetable plants in medium-sized pots, while the John Innes No. 3 is used for heavy feeding vegetables and flowering plants in hanging baskets and containers.

  1. Feeding

The John Innes No. 2 compost will feed for up to 5 weeks while the John Innes No. 3 compost will feed for up to 4 months using slow-release nutrients. 

  1. Nutrients

In the John Innes No. 2 compost, plants enjoy the benefits of added Potassium humate because it aids the creation of healthy soil conditions using aeration which makes the soil easier to work with. It also has double the nutrients in the No. 1 compost. 

In the John Innes No. 3 compost, plants enjoy the benefits of Slow-release fertiliser because they work by releasing a measured amount of nutrients when watering. This will ensure the compost feeds for a longer period before it needs to be fed again. It has thrice as much fertilizer added as the No 1 compost.

  1. Composition

For each cubic metre of mix in the John Innes compost 2 7 Loam, 3 Peat, 2 Sand, 0.6kg ground limestone, 2.4kg hoof and horn meal, 2.4kg superphosphate, and 1.2kg potassium sulphate are added. While in the John Innes compost 3 7 Loam, 3 Peat, 2 Sand, 0.6kg ground limestone, 3.6kg hoof and horn meal, 3.6kg superphosphate and 1.8kg potassium sulphate are added.

  1. pH Level

John Innes No. 2 compost has a pH level in the range of 5-6 which supports the provision of a medium level of nutrients formulated to feed and support strong, healthy plant growth. While the John Innes 3 compost has a slightly acidic pH of 6 to 7, meaning that it is suitable for a large array of plants and will benefit from access to the nutrients.

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Last Modified: May 23, 2022