Composts

The term Compost can have more than one meaning; there is Compost the growing medium and
Compost the material produced in a compost heap (see Composting).

For the purposes of this information sheet we will be discussing Compost the growing medium.

Types of Compost:

Composts comprise a growing medium such as peat with added nutrients and sometimes other
materials such as sand or grit. Peat is still the most effective medium but alternatives are now being
used to prevent environmental damage to the peat bogs.

There are 3 main groups of Compost:

1. Peat Based Composts e.g. Levington, Murphy's, J. Arthur Bowers
2. Low Peat/Peat Free Composts e.g. The "Nature's Way" range  of low peat composts by Levington
3. Soil based Composts e.g. "The John Innes range"

Range of Composts:

Within each group of compost there is a range of composts formulated to do different tasks.
The main types are:

Seed compost: usually a fine textured compost and relatively low in fertilizer to avoid "burning"
seedlings.

Potting Compost: Coarser in texture and higher in fertilizer for greedier more mature plants.

Multi-Purpose Compost:  Does exactly what it says it does, a half way house between a seed and a
potting compost - a jack of all trades (master of none?)

Tub/Hanging Basket Compost: A recent development and a worthwhile one. Basically a potting
compost with added water retaining material and/or slow release fertilizer.

Rose/Tree/Shrub Compost: Basically a potting compost with enough added fertilizer to last a whole
season - for larger, mature plants.

Ericaceous Composts: Formulated without using Lime to suit "Lime hating plants".
Compost with Insect Control: Expensive and with a short shelf life as the insect control element
dissipates quickly.

Bonsai, Alpine, Cactus, Orchid, Citrus, Houseplant, African Violet etc.

The John Innes Range:

• John Innes Seed Compost is self explanatory.
• John Innes No.1 is formulated for younger/small plants or cuttings.
  Very similar to the seed compost.
• John Innes No.2 has a higher fertilizer content than No.1 so is suited to established plants.
  Equivalent to multipurpose compost.
• John Innes No.3 has a higher fertilizer content than No.2 and is suited to larger/mature plants.
  Equivalent to potting compost.

N.B. - Being soil based, John Innes composts tend to be heavier than peat based ones so are
not available in sizes above 25 Litres. Being soil based they are low in Peat.