How to create a good compost?
As every gardener knows, one of the key things you need if you are going to grow plants is good soil.
When using permaculture this necessity can sometimes be challenged; for example, in very dry or extreme (very dry/very wet) climates such as Mediterranean, some people recommend using no soil at all but instead growing all of your plants in gravel or small pebbles.
This technique, suggested by for example Hemenway (1), is known as xeriscaping and might be worth a try if your garden is particularly prone to drought. On the other end of the spectrum, aquaculture is a technique that involves one’s crops being entirely submerged in water, which has been used for centuries in Asia and whose modern proponents include Christenson (2015) (2).
If you prefer to plant your crops in the ground, however, it is definitely worth adding compost to them to aid their growth by enriching the soil and adding much-needed nutrients. One of the most fulfilling (and cheapest!) ways to do this is to make the compost yourself. Below I will share some tips on how to create top-quality compost in an easy way.
GREEN AND BROWN
Probably the most important thing to remember when you are making compost is getting the proportion of materials right so that the decomposition will happen in a way which keeps the nutrients alive. Usually this is spoken of as the relation of “green” to “brown” materials; green being anything fresh with a generally higher balance of nitrogen, such as freshly cut plants and grass, and brown being dry, more carbon-rich materials such as straw, sawdust and ash. To get rich compost you need around a 50:50 ratio of brown: green. This is by necessity a rough guide as you are not expected to be closely measuring the materials as you add them, but is useful to remember. For more detailed suggestions on the exact ratios of carbon to nitrogen and how much of each material is present in many commonly-found materials, try checking out (3) and (4).
One thing that is worth getting hold of if you can is some manure, which is very high in nitrogen and so can be added in small quantities as the kind of ‘spice’ of the compost recipe.
HOT AND COLD
There are two main techniques for making home-made compost. Cold compost means gathering the materials together in a pile and leaving them to decompose naturally at their own rate. For this technique you still need to get the ratio of “green” to “brown” to be about even but there is less work involved as once you have mixed the materials together you simply need to leave it to its own devices. This technique is useful for a small kitchen compost pile which you can add kitchen waste to on a daily basis, balancing it out with carbon-rich “brown” to keep the ratio healthy. A slightly more complicated method is that of hot compost, which I will concentrate on in this article.
THE BERKELEY METHOD
The style of hot composting with which I am most familiar is known as the Berkeley Method as it was apparently first developed at the University of California in Berkeley (3). There are a number of reasons why you may want to utilise this method instead of cold composting:
– It is much quicker than cold composting so you can use your compost more immediately
– The high temperatures produced by the decomposition kill any unwanted seeds which may be present, so the compost is safe to use on your garden
– If you want to get really technical and “multiple functions for each element”, you could use it as part of a water-heating system (see for example 5)
Some things to consider about this style of hot composting:
– It uses a lot of material right at the beginning so you need to have access to a large amount of organic matter all at once
– It also uses a fair amount of space – 1m x 1m x 1m is the usual recommended minimum – so is maybe not that practical if you are just planting up your back garden
Having taken these factors into consideration, if you feel the Berkeley Method is for you then read on!
HOW IT WORKS
The idea of hot compost is that you collect enough green and brown material (in the correct ratio) together that when you pile it up in a heap which you then aerate by turning it creates really great conditions for speedy decomposition to happen. This is due mainly to the presence of aerobic bacteria, which are the fastest digesters of organic matter (6). They are the reason for the need to create the right balance of carbon to nitrogen, and they also need a significant amount of oxygen to survive, which is why hot compost is turned to aerate it. The Berkeley Method has developed an exact time period when it’s best to do your aerating, which culminates in finished compost in just 18 days.
YOU WILL NEED:
– A space to put the pile which is over 2m x 2m
– A mix of green and brown materials
– Lots of water ready to hand (if you have a hose that will reach the pile this is probably easiest)
– Tarpaulin or other material to cover the pile when you leave it to rot
TOOLS:
– Pitchfork
– Shovel
– Wheelbarrow
STEP 1: GATHER MATERIALS AND CHOOSE SPACE
As with any task which involves creating something, the first step is to source what you will use and choose where you will place it. As mentioned, the hot compost pile you are creating needs to be at least 1m x 1m x 1m square, and you will be turning the compost so ideally you need enough space for 2 compost piles, plus manoeuvring space to give you the chance to turn it. It can be bigger, but you will probably want to keep it in a cube-like shape when first creating it (though the sides will inevitably slip down as the decomposition takes hold) so bear this in mind when siting the pile.
Next you need to find what you will put in the hot compost pile. In order to maximise efficiency, it is probably best to start your pile immediately after doing some kind of big weeding/grass cutting/pruning/woodwork/fire making/all of the above; as all of these activities create by-products which are perfect materials to make compost with. Gather all of the materials together next to where you will place the pile so that it is easy to pile them on top of each other. Remember that very roughly, you want about a 50:50 mix of green (e.g. fresh plant matter and especially nutrient-rich plants such as clover, nettles, comfrey, alfalfa) to brown (e.g. sawdust, ash, straw, and dry plant matter). The other essential thing you will be adding is water, and lots of it, so if your pile is within reach of your garden hose this will make creating the compost a lot easier than if you have to bring water in from afar.
STEP 2: MIX INGREDIENTS
Using the pitchfork and/or shovel, begin layering up your ingredients in the space you have chosen. Just start piling them on top of each other, a few pitchfork-fulls at a time – going from the ‘brown’ material to the ‘green’, to ensure an even mix. You can also add the manure ‘spice’ every few layers.
Once your pile is big enough you can begin to shape it. The most optimum shape is as close to a cube as you can manage; the corners ensure that the pile can stay relatively intact as the decomposition takes hold. You can create the corners by taking your pitchfork, sticking it into the middle of the pile, and then moving it gently up and down as you pull back from the centre to the edge. Do this on all corners, anytime you see that the pile is beginning to slip.
Along with your plant-based materials, key ingredients are air and water. To aerate the compost pile, again use the pitchfork by sticking it into the pile at regular intervals to ensure there is some air flow needed.
As the pile grows, you need to be adding water every couple of layers, or every 4 inches (10cm) or so. When adding the water, pour it liberally onto the pile, ensuring everything gets saturated. The pile will soak up a lot of water before it begins running out of the bottom, but even when it does, you can still keep adding more as you pile up more dry ingredients.
STEP 3: COVER AND LEAVE
Once the pile is at least 1m tall, 1m wide and 1m long it is ready to leave. Douse the pile once more with water, and do some final shaping with the pitchfork to ensure the form is capable of optimum conditions. Then take the tarpaulin, and cover the compost pile. You may wat to weigh the tarpaulin down with rocks, tyres, bricks, pallets or other heavy items.
Now it is time for the first period of decomposition. This is four days. It is probably a good idea to note down the date when you will need to turn it. Then just leave the pile for the microbes to get on with their work.
STEP 4: THE TURNING
After 4 days have passed it’s time to turn the compost over. Before taking any action, you may wish to test the efficacy of your pile by sticking your hand into the centre, or (if for some reason you don’t feel like getting half-decomposed material all over your hand), poking a stick inside to make a hole. The hole should be steaming, or your hand should be hot. When you turn the pile over you will move all of the really hot central material to the edges so that the whole pile will become evenly rotten. It also allows for more aeration to add oxygen to the mix.
To turn the pile, take it apart from the top down, layer by layer in the opposite way from which you built it. A pitchfork is probably the handiest tool to do this with. Ensure that much of the thick, hot stuff gets moved outwards and the things which have not begun fully rotting yet go into the centre where they can get in on the heat action. Every few layers, add water again as previously. As with when first creating the pile, try to make the corners as accented as possible by wiggling the pitchfork from the centre to the edges.
Once you have rebuilt the pile next to the place where it originally was, cover it with the tarpaulin again. The next times you have to turn the compost are every two days for fourteen days.
STEP 5: REST AND REPEAT
On day six, 2 days after the first turning, when you come to your compost pile the centre should be between 55 and 65 degrees Celsius. If it is too cool you will not see steam rising when you put your hand inside and if it is too hot it may develop a kind of white mould (3). You may wish to use a thermometer to check the temperature. If it is too hot, make sure you move all of the central material to edges and the edge material to the centre, and aerate the entire pile with your pitchfork. The mould should disappear once the compost cools down enough.
Every time you turn the compost, follow the same guidelines as step 4. You need to turn the compost every 2 days after the first turning, so on day 6, day 8, day 10, day 12, day 14, day 16 and day 18.
STEP 6: ENJOY YOUR NEW COMPOST
After 18 days, when you come to turn the compost, you ideally want to be encountering rich, dark brown earth, with all the materials fully broken down. This compost is now ready to use. As with all compost, it may be a little strong to place directly onto seedlings and young plants, but is an ideal addition to potting mix or can be used on trees or in garden beds.
Creating healthy soil is one of the most basic and rewarding things we can do. As well as benefiting our plants and helping us to grow things for food and other uses, we are contributing to the wider ecosystem and helping the earth to regenerate. An enjoyable task indeed.
REFERENCES
1. Hemenway, 2009. Gaia’s Garden: A Guide to Home-Scale Permaculture. Chelsea green: New York
2. Christenson, 2015. Aquaculture: Introduction to Aquaculture for Small Farmers. CreateSpace Independent Publishing Platform: Seattle
3. Deep Green Permaculture, 2015. ‘Hot Composting – Composting in 18 Days’.http://deepgreenpermaculture.com/diy-instructions/hot-compost-composting-in-18-days/
4. Planet Natural, 2015. ‘Carbon-to-Nitrogen Ratios’. http://www.planetnatural.com/composting-101/c-n-ratio/
5. Wheaton, Paul, 2009. ‘500 showers heated from 1 small compost pile how-to tutorial’. Youtube Video
6. University of Illinois Extension: Composting for the Homeowner. ‘The Science of Compost’.http://web.extension.illinois.edu/homecompost/science.cfm
This article is produced by Geoff Lawton and his PDC course. For dozens of additional videos and learning resources, sign up (free!) for Geoff’s Permaculture Circle here: start.geofflawtononline.com/permaculturecircle/
