Composting is one of the most important activities in a sustainable, organic polytunnel garden. Here are some tips for composting that should help you to create good compost and keeping your compost heap working well over the summer months:
Nitrogen and Carbon in a Compost Heap
Creating a good compost involves a basic understanding of the different sorts of material in a compost heap. The materials are usually grouped into two categories – carbon rich ‘brown’ materials and nitrogen-rich ‘green’ materials. Both types are needed in order to create a good-quality compost. Brown materials include cardboard, straw, twiggy material, wood chips and bark. Green materials include green leafy matter, grass clippings, and fruit and vegetable scraps.
In order to get a good mix in your compost, you should add ‘brown’ and ‘green’ materials in thin layers. Adding in thin layers allows for the right conditions for aerobic decomposition and helps to ensure that your compost does not become too wet or too dry.
The Importance of Oxygen in a Compost Heap
When we create compost, we are aiming for aerobic decomposition. Aerobic decomposition takes place with oxygen, anaerobic decomposition takes place without it. Oxygen is used by microbes in order to process waste efficiently and effectively. Mixing or turning your compost heap once or twice a month, especially over the summer, can significantly speed up the decomposition process and help to make sure that the aeration of your heap is sufficient for microbes to do their best work.
The Importance of Moisture in a Compost Heap
When making compost, it is also important to make sure that it does not become too wet, or too dry. When there is not sufficient moisture, microbes will not be able to do their job. Problems will also arise if your compost becomes too soggy. You may have to water your compost in the summer months if the weather is dry in order to get the best results.
The NPK Balance in Compost
In addition to considering all the above, creating really good compost is also about making sure that your heap has adequate levels of nitrogen, phosphorus and potassium – the three main nutrients required by plant life. An average home made compost will have a nitrogen value of 0.5 %, 0.27% phosphorus and 0.81% potassium. By adding a good range of items to your compost heap, and making sure its microorganisms can do their jobs, you can help keep a good balance of these three nutrients in your polytunnel, as well as supplying trace minerals and micro-nutrients needed for good plant health.
Read our guides to find out more about methods that you can use to create compost for your polytunnel garden.
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.