COMPOSTING

Soil only contains a small percentage of organic matter (humus, roots and microbes), but it is essential to enable plants to grow organically. We can create organic material for the soil by making our own compost. This is where leaves, food waste, garden waste anmd cardboard can be used to create our own compost bin.

Organic matter such as leaves, vegetable peelings, or coffee grounds decompose naturally.

Composting is the art of making that process more efficient by creating the right conditions for bacteria to break down material more quickly and convert it into food for our soils. By feeding soil, rather than plants, we improve the symbiotic relationship between plants and soil, benefitting both.

Composting has several benefits:

It is cheap and easy to get started.
Making your own compost puts nutrients from your plants back into your soil
It is ideal for topping up no-dig beds
Compost heaps are a haven for microorganisms which help improve soil health and can be a home for larger beneficial animals e.g. frogs and slowworms.
Making your own compost has a lower carbon footprint and is cheaper than buying it and its in the right place – in your school garden. If you still need to buy, choose peat free composts
Pupils can see the composting process in action

Making or choosing a bin

Here are a few things to consider:

Make or buy, or get for free? – this will depend on your DIY skills and your budget. Sometimes secondhand bins are available for free. Making is generally cheaper than buying. A simple compost bin can be made from four pallets very easily. Buckinghamshire residents can get a discount on bins through www.getcomposting.com.
Appearance – if this is important to you, you may prefer to buy a smart looking bin.
Types of bin – if you want anything other than a rectangular box on the ground, consider buying.
If buying a bin, the black plastic ‘Dalek’ type bins work well.

Options for making a bin

Slatted sided bin ( aka 'NA' Bin)

Cheap and easy to make from four pallets. (easily found or donated)
Large (approx. 1.5m3)
Good air flow to edges, but not to middle
Edges can dry out
Poor insulation. Improve insulation by putting cardboard against the pallets.
Fine for a large volume (>1m3) or if time to produce compost is not important.
Easy to cover with a tarpaulin to keep the rain off.
Not rodent proof

Solid sided bin

Similar to a NZ bin, but more expensive depending on where you can source the timber
Solid sides give better insulation, especially for a twin bin (two bins side by side sharing a dividing wall), but there is no air movement.
asy to make rodent proof by adding mesh on the ground to prevent them burrowing.
Fit slatted pieces to the front of the bin to make it easy to empty the bin.
Can be fitted with a lid (but be careful of squashing fingers). A tarpaulin cover is adequate
Typically 1 m3 per bin

For measurements to make your own click here

Dalek’ type bin

A generally good all-rounder for garden use
Relatively cheap. (discounts for Buckinghamshire Residents available)
easy to set up and use.
Suitable for limited input. (typically 220 or 330 litres volume)
Usually made from recycled plastic
Difficult to remove mulch

Insulated Bin (e.g. Hotbin)

Heats up quickly
Good for reaching thermophilic stage
Expensive
Need to maintain good C:N ratio for it to work well.
Needs regular feeding & aeration
100 or 200 litre sizes

Tumbler

Easy to aerate and empty
Good for initial composting stages
Material can get tangled around the horizontal axis.
Pest proof (no contact with ground)
Heavy to turn when full.
Many different designs now available.
Typically around 200 litres capacity