When planning your allotment a space for a compost bin or two is essential.
Why would you turn down the opportunity to have some free soil improver?
A compost bin is a structure that keeps all your compost together rather than in a heap. Both work the same way if treated correctly but a bin will take up less space.
Planning the space for two bins at the start is a good idea so you can have one bin full and ‘maturing’ while you fill the other bin.
In some areas where the conditions are right and the decomposition rate is very good you may get results from the bottom of one bin while still filling it up at the top.
If you start with one, with enough space for two, you cannot lose.
Some compost bins may need aerating to keep the process going at full speed and removing the contents from one bin and placing in a second is a good way to do this. The decomposition of plant material by the ‘bugs’ uses oxygen and if the bin contents are too compacted the oxygen will be unable to enter. Turning your bin increases the oxygen and speeds up the decomposition process.
The ideal tool for aeration and moving compost is a good fork – see our Forks section
The right site
Ideally your compost bin should be in a reasonably sunny site on bare soil. If you have to put your compost bin on a solid surface like concrete or patio slabs add a thick layer of paper and twigs or existing compost to the bottom of the bin so the worms and other creatures can colonise. Choose a place where you can easily add ingredients to the bin and get the compost out.
Getting the mixture right
The key to good compost lies in getting the mixture right. The contents are referred to as ‘Greens’ and ‘Browns’ and here some examples.
Tea bags, Grass cuttings, vegetable peelings, salad leaves, fruit scraps, old flowers and nettles, coffee grounds and filter paper, spent bedding plants, rhubarb leaves.
Crushed egg shells, egg and cereal boxes, corrugated cardboard and scrunched up paper, toilet and kitchen roll tubes, garden prunings, twigs and hedge clippings, straw and hay, bedding from vegetarian pets, ashes from wood, paper and lumpwood charcoal, sawdust and wood chippings, vacuum cleaner contents, tissues, paper towels and napkins, shredded confidential documents
To keep decomposition going at the best rate you need to keep your greens and browns properly balanced with the right amount of water and oxygen. A 50/50 mix of greens and browns is the perfect recipe for good compost.
If your compost is too wet and gives off an odour, add more browns.
If it’s too dry and is not rotting, add some greens.
Air is essential to the composting process and by mixing material up, as you fill your bin, it will create air pockets and help keep your compost healthy
Things to keep out
Any cooked vegetables, meat and dairy, diseased plants, dog poo or cat litter, or baby’s nappies.
Putting these in your bin can encourage unwanted pests and can also create smells.
Also avoid composting perennial weeds such as dandelions and thistles or weeds with seed heads. These seeds will remain inactive until you use your compost, then sprout up in abundance!
How can I tell its working?
If your bin feels warm when you open the lid, excellent, decomposition is under way. You can use a digital thermometer to check the temperature below the surface of the bin. Keep the thermometer just for this purpose, your heap is full of microorganisms that are great for decomposition but not good for you.
Keep an eye out for slugs and snails and dig down a little and see if you have worms. Worms are great in compost bins as they help digest plant materials and create air holes through the contents. You will find small red worms in the bin, these are compost heap worms, you will not find the big earthworms found in the garden.
Once you have a good depth of compost in your bin use your fork to turn the top layer into the under lying layers. Give it a good mix to get the new material down into the ‘active’ decomposition layers below the surface.
You can purchase ‘compost accelerator’, this is a dry mixture that adds enzymes and other microbe nutrients to help the bugs get going.
If your bin is a bit compacted open the side and drag the contents out and then put it all back, or use your second bin transferring the contents of bin 1 into bin 2.
How long will it take?
It can take between nine and twelve months for your compost to become ready for use, but given ideal conditions it may be ready sooner than that. If your bin gets to a high temperature decomposition happens sooner. All you need to do is wait and let nature do the work.
In winter the lower outside temperatures slow down the process and the warm summer days speed it up, just keep on adding greens and browns to top up your compost.
Once your compost has turned into a crumbly, dark material, resembling thick, moist soil and gives off an earthy, fresh aroma, you know it’s ready to use.