How to make compost at home

Here are some tips on how to make compost that is most helpful for gardening. I have a simple cold compost pile, but someone with a green thumb may want to create a hot compost pile to quickly create very nutrient-rich compost.

How to compost:

• Choose your composting site in your garden.
• Decide whether you would like a compost bin or pile. A compost bin can be as simple as an open-top cube made from wood palettes. If you decide on a pile, you may wish to use a wire or fence to protect it from pests.
• You can turn your mixture over every week or so using a utensil to allow airflow, as compost decomposes in the presence of oxygen.
• Keep the pile damp. Add a splash of water to your compost, and do so whenever it starts to run dry (which is unlikely to happen in Ireland...)
• Break up bigger, more solid materials by cutting them to ensure that oxygen is getting through the compost.
• You don't want the pile to be too wet.
• If the compost becomes too wet or smells rotten, mix in dry brown materials such as dry leaves or ripped up cardboard and turn the pile.

What you can use for compost:

In Sligo, private rubbish collection companies offer a composting bin that is collected fortnightly, and collects biodegradable waste. My family makes use of this, while also having a compost pile in our garden that creates compost that is useful for gardening. We have one compost bin that is collected, which contains organic waste that we don't throw in the garden pile, as it may attract pests.

You may want to avoid having meat and fish, animal bones, dairy products, oils and fats and dog or cat waste and kitty litter in your compost bin/pile, as it will start to smell and attract pests. Avoid adding weeds and diseased plants unless you have a properly maintained hot compost pile, in which the heat will kill weed seeds and diseases. Also don't add anything treated with herbicide or pesticide chemicals.

Try to keep a healthy mix of green and brown waste. Green waste supplies nitrogen to the compost which helps to build the cell structure of the soil. Brown waste provides the organisms that break down the soil with carbon.

Good materials for a backyard compost pile include:

• Fruit and vegetable scraps
• Coffee grounds and paper coffee filters
• Loose tea leaves and fully compostable tea bags
• Eggshells
• Fresh grass clippings (keep in moderate amounts when hot composting)
• Garden trimmings
• Fallen leaves
• Straw
• Small amounts of untreated wood or sawdust
• Shredded non-glossy paper or newspaper
• Shredded non-glossy cardboard
• Nutshells
• Hair
• Seaweed that has been rinsed of excess salt

The main types of composting:

Cold or passive composting is the most simple, low-effort way to compost. You build a pile of organic matter and allow it to decompose over time without managing its temperature or turning it frequently. You let it decompose in a pile bin over a year without much intervention.

Add brown and green materials as you accumulate them, without thinking too much about the brown to green ratio. Bury fruit and vegetable scraps in the middle of the pile to discourage pests.

Hot or active composting is a faster method that delivers results within one to three months. A well managed pile can heat to about 54 to 71 degrees Celcius as microorganisms break down the materials, you can check this with a compost thermometer. These higher temperatures can also help kill weed seeds and disease-causing organisms.

Make sure to have the right mix of green and brown materials to create a carbon to nitrogen balance, this should be roughly 2 to 3 parts brown materials and 1 part green materials. When the majority of the compost is made up of green materials such as grass clippings, the pile can become overly wet and compacted, and unpleasant smelling. Too many brown materials such as autumn leaves can slow decomposition.

The compost pile should be at least 3 feet/90cm wide and 3 feet/90cm high. Although, an extremely oversized pile may be difficult to turn and aerate.

Cut materials into smaller pieces, as they will decompose faster as more surface area is exposed.

To make a hot compost pile, start with a layer of coarse brown material such as small twigs, dry leaves, or shredded cardboard. Coarser materials at the bottom improves airflow. Add a layer of green materials such as vegetable scraps, fresh grass clippings, or garden trimmings. Continue altering browns and greens until the pile reaches at least about 3 feet/90cm high. Moisten the materials as you build the pile, the finished mixture should feel as damp as a wrung-out sponge, but not dripping wet. Keep air moving through the pile by mixing it periodically.

A well-built hot compost pile may begin heating within a few days. Use a compost thermometer to check the centre of the pile. Temperatures between 43 and 71 degrees Celsius indicate active decomposition. The pile will heat up after each time it is mixed or turned.

As the centre begins to cool, turn the pile so that the materials from the outside move toward the middle.

Worm composting or vermicomposting uses red worms to break down food scraps and other organic materials into a compost excellent for nitrogen enrichment. It is a very space efficient composting method that can be done in a relatively small container. It doesn't require a garden, and can even be done indoors in a container. Worms are affordable and can be found online or at garden stores.

Getting started can take some preparation because you need suitable bedding, the right type of worms and a well-ventilated container. Once established, a worm bin is relatively easy to maintain by adding appropriate kitchen scraps regularly and keeping the bedding moist but not waterlogged.

How to know if your compost is ready:

Finished compost should be dark, crumbly, and earthy-smelling, with a few pieces of the original ingredients remaining. The pile should also stop heating up after each time it is turned. Once active decomposition has finished, allowing compost to cure for several weeks can help stabilise it before you add it to garden beds, containers or planting holes.