All too often gardeners start composting with great excitement and enthusiasm, only for interest to wane as the results disappoint.
Here is a quick guide to help you produce the best compost in whatever composting bin you choose.
Vegetables grow best when enriched with home made compost. Photo - photolibrary.com
Oxygen is crucial to a good brew. Turning the compost allows air into the pile to aid the process of decomposition. The importance of circulating oxygen is the reason its best to avoid adding materials such as grass clippings in bulk. These can mat together, preventing good air flow. Compost turning can be done with a fork or a specialised aerating tool shaped like a metal spiral.
Composting is like baking in that to get a good result you need the right balance of ingredients. Composting is easier though because there are only two main ingredients: carbon and nitrogen. Aim for a ratio of these two ingredients of 25:1. To give you an idea, shredded newspaper is high in carbon, with a ratio of approximately 170:1 whilst green vegetable scraps are higher in nitrogen with a ratio of around 30:1. You can judge how the ratio is going by the texture of your mix. If the compost is soggy with green waste, buffer it with some shredded paper or dry leaves; if it is too dry add more leafy greens and soft prunings. Problems often occur when the ratio of ingredients is incorrect.
Bins lined with chicken wire are easy to build. Photo - photolibrary.com
The ideal minimum volume for compost is 1m3. This size will generate sufficient heat to destroy weed seeds and speed up the composting process. Avoid adding weeds to smaller volumes of compost, as the seeds will survive the process.
Compost should never be wet or dry, but should have the consistency of a wrung-out sponge. You may need to add water in summer as some composting units can dry out when temperatures are high. In times of high rainfall, cover the compost.
It does not matter what ‘oven’ you cook your compost in as the compost that results is the same whether it is slow or fast cooked. Units with a larger capacity and good aeration generate the most heat and therefore kill off weeds more effectively and compost faster.
Composting is a naturally acidic process. Adding a handful of lime every now and then will aid in the decomposition of waste, encourage worm activity and discourage unwanted insect activity.
Heat is an essential part of the process. Photo - Marv Bondarowicz
Those with backyard chickens can use a layer of chook manure within the compost. Gardeners with access to cow manure can do the same. This enriches the compost and creates healthy rich soil. Never add dairy or too much manure though, as this can have a negative effect.
Accelerators and Activators
Commercially available compost accelerators add bacteria and fungi to the mix to help decomposition. Do it on the cheap by retaining some of your prior compost for inclusion in the next batch, or adding a bit of garden soil, which will also naturally contain these activators.
Choosing the right compost system
Features: A double insulated plastic unit with the addition of an internal “lung”, which allows air to penetrate the core of the compost, reducing composting time. A tap at the base of the unit allows leachate to be collected and applied to plants.
Ideal for: People wishing not to turn their compost manually, but instead let it aerate itself. The totally sealed construction is also vermin-proof.
Rapid Compost Tumbler 310
Features: Durable plastic construction on a raised frame allows contents to be emptied directly into wheelbarrow. The side handle allows the drum to be easily rotated to aerate the contents.
Ideal for: Gardeners who produce larger amounts of green waste and wish to compost it as quickly as possible. The speed in which the unit works is governed by how frequently you turn it and the materials contained. This unit is also vermin-proof.
Reln Worm Farm
Features: Plastic unit that is raised on legs allowing liquids to be easily collected. It is sealed against pests while still allowing worms to breathe
Ideal For: Balconies and units where space is limited and wastes are mainly food scraps. People with larger gardens will also need a compost bin for bulky waste and waste that is unsuitable for worms. If used correctly the unit should produce no unsavoury smells. The liquids produced can be diluted with water and applied as a fertilizer on pot plants.
RRP: $120 + Worms
Gedye Compost Bin
Features: This basic design sits on the ground and is one of the cheaper store-bought composting options. It can work as well as more expensive units, providing you turn it often using either a fork or other aerating implement.
Ideal for: Gardeners who move their compost bin around their gardens as they go. People wanting a cheaper alternative who are willing (even keen!) to turn their compost.
Features: The timber compost bin is the traditional choice. You can construct your own out of new or reclaimed materials in various styles. It can be several bays wide to accommodate various stages in the compost cycle. The ideal size of each bay is 1m square to generate the fastest, hottest compost.
Ideal for: People who have a little more room to spare and do not mind getting in amongst their brew.
RRP: $0 and upwards, depending on materials.
Metal Mesh Bin
Features: A very basic construction suitable for holding excess materials waiting to get into your compost bin. It can also operate as a compost bin in its own right.
Ideal for: gardeners with room to spare and plenty of materials to compost, looking for a cheap and easy method. The system works best if compost layers are added with care to balance the ingredients in the mix.