Making your own compost: the complete guide

Make waste useful, turn it into a resource

Inspirations / How to

22/06/2021

Estimated reading time 7 minutes

Compost is a humus-rich soil that you can obtain from the decomposition of organic material: kitchen scraps, garden waste and pruning residues. With home composting you effectively replicate, but at a faster rate, the natural process whereby plant and animal remains that are deposited on the ground decompose and are recycled. This process is performed by microorganisms, insects, earthworms, etc.

Today we will talk about composting, explaining why and how to compost using a household composter (compost bin). Finally we will illustrate how to build a DIY garden composter.

Do-it-yourself compost: what are the benefits?

Why does it make sense to make your own compost? Making your own compost is a great way to:

  • Make your vegetable patch and garden fertile with a quality fertiliser, thereby cutting down on the use of chemical fertilisers and eliminating the need to purchase topsoil.

  • Repurpose household and green organic waste, turning your home into a kind of circular economy.

  • Reduce the amount of grass clippings and pruning waste you dispose of, meaning fewer trips to your local recycling centre.

  • Take advantage of local council incentives, where available.

So, composting enables you to recycle useless waste into compost so that it can enrich your garden soil and vegetable patch with nutrients (which vary depending on its constituents), make it more porous (therefore soft and more workable), and more capable of retaining water.

Mature compost does not smell and is stable (meaning that it doesn’t contain any undecomposed matter). It is suitably dry rather than moist (you can sift it) and soft, and also has a rather homogeneous appearance, meaning that the original constituents are no longer distinguishable, with the exception of larger pieces of wood, which you can throw back in the composter. Only when your DIY compost is mature should you use it in the vegetable patch, garden—on the lawn, flower beds and potted plants—or orchard. Depending on the climate and how you go about composting, it can take from 3-4 to 10-12 months to produce.

You can use your self-made compost when preparing soil before sowing or transplanting—not only vegetables and flowers, but also trees and shrubs—and, if necessary, when growing. By the way, check out our guides on preparing a vegetable patch and how to make an orchard.

And that’s not all: you can also use compost to make winter mulch, which we talked about in our article on how to protect plants from the cold.

How to make compost at home

The key ingredients of DIY compost are organic waste, which can be divided into 2 main categories: nitrogen-rich materials (green, fresh, moist) and carbon-rich materials (dry), which should be combined in a volume ratio of 1:2. Fresh materials include discarded vegetables and fruit, food scraps, coffee grounds, tea bags, egg shells, as well as grass mowed by your lawnmower or brushcutter and the green parts of plants, for example twigs and leaves trimmed by your hedgetrimmer.

By contrast, dry materials that can be used to make your own compost include fruit kernels, dried fruit shells; dead leaves (limit the amount of thicker and tougher varieties, such as pine needles and magnolia leaves), pruning debris from trees and shrubs, shrivelled flowers, the remains of garden crops; wood sawdust and, in lesser quantities, paper (including napkins and tissues). Wood waste should preferably be cut and chopped—ideally at the time of removal using pruning tools—or shredded using a bioshredder. It is also advisable to crush nuts and shells of dried fruit into fragments. When filling your home compost bin with organic waste, alternate dry and fresh layers, starting with a layer that facilitates airflow and drainage. Finally, remember to add a little soil or, if possible, compost to act as an activator to kick-start the composting process.

Don't risk using materials that are potentially harmful: make sure that the compost constituents are non-toxic. So, you shouldn’t use parts of plants that are diseased or have been recently sprayed (less than 3 months ago) with pesticides, or weeds, clippings from grass treated with herbicide, dirty pet bedding or varnished/treated sawdust. Alternatively, if you prefer an exclusively plant-based compost, avoid composting animal products, such as meat, fish and dairy.

To make your own compost you not only need organic waste in balanced proportions, but also oxygen and water. Composting is an aerobic process, meaning that it takes place in the presence of air, so no nauseating odours are released as the organic material decomposes. In addition to not compressing the contents of your composter too much, promote aeration by inserting light material—such as dry leaves, sawdust, coarsely chopped wood, pruned branches that have been chopped up, etc.—and, from time to time, mix the composting mass.

Humidity is also important for proper composting. Make sure there is neither too little nor too much water: if you pick up a handful of the compost and squeeze, it should not drip water or crumble away. For this reason, your garden compost bin needs a lid that protects the contents from rain, otherwise you will need to aerate and mix the composting mass to evaporate excess water. Conversely, in times of drought we recommend watering it.

Since we all mow our garden lawns at least fairly regularly, it makes sense to use grass clippings in your home composter. Are you looking for a new lawnmower or brushcutter? Here you can find our tips on how to choose the right lawnmower and which is the best brushcutter for your needs.

To transport waste and mature DIY compost to and from your compost bin, as well as for carrying the materials and equipment to build your garden composter, you can use a wheelbarrow. Alternatively if you need to travel longer distances, or just for the sake of convenience, get yourself a transporter.

How to build a DIY garden composter

We said that home composting gives value to the organic waste in your home and garden, by converting it into a resource useful for looking after your plants, vegetable patch and orchard. But how do you make compost at home? You need a composter, otherwise you can opt for simpler systems (heap or pit).

Compared to other systems, a domestic composter has a series of advantages:

  • It enhances your garden’s appearance: it saves space, looks tidy, hides the composted material and usually blends in well with the vegetation.

  • It limits odours thanks to the ventilation holes in its sides and, in some cases, also on the lid.

  • It keeps pets and wild animals at a distance.

  • It enables organic material to be added via the lid, and mature compost to be removed through the hatch at the bottom.

  • It protects your DIY compost from rain as well as heat and cold (the latter two, if extreme, can slow down the process), so you can better keep your composting under control.

So, to make compost at home, use a garden composter that you can buy or make yourself. In both cases, the dimensions of your composter should fit your available space and be proportionate to the amount of waste produced. If you chose to buy one, you are spoiled for choice in terms of shapes, sizes, materials and price (and if you don't have a garden, there are even balcony composters).

You can build a DIY garden composter easily: all you need are four wooden stakes planted in the ground as corner supports, wooden boards or planks to make the walls and plenty of screws to fix the boards to the posts. There should be a finger-wide gap between the boards to allow oxygen to penetrate inside the composter. You can also use wooden boards to build a lid at the top of your composter. By contrast, the bottom should be left open, or at least aerated, to allow the "fourth ingredient" needed for composting to access the materials from the soil: microorganisms, insects etc. Provide a hatch at the base of the composter for removing the finished compost

Alternatively, you can use pallets, which already have spaces between the boards, to create the walls and lid of your composter (consider waterproofing the latter by covering it with plastic sheeting).

If you need to cut wood to build your DIY garden composter, you may need a chainsaw suitable for DIY projects, such as an electric chainsaw, an entry-level petrol chainsaw or a medium-power chainsaw. If you're lucky enough to have a felled tree trunk lying around, you could saw it into planks — follow our tutorial on how to make planks from a tree trunk.

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