Compost is the very best food you can give to the plants in your garden. However, making really great compost requires the right mix of ingredients. This video demonstrates how to mix greens and browns with air and moisture to produce good compost.
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How to Compost
Most people think composting is as simple as throwing all food and garden waste into a container and leaving it there for a couple of years. While you will get compost that way, you can produce much better compost and get it much more quickly if you follow these simple guidelines for the perfect recipe.
There are 4 ingredients for good compost: greens, browns, air, and moisture. These 4 need to be balanced correctly for best results.
The ingredients you add to a compost heap contain carbon and nitrogen. The ratio of carbon to nitrogen determines whether we label it a ‘green’ or a ‘brown’.
- Ingredients that have a relatively high nitrogen content and a carbon-to-nitrogen ratio below 30:1 are called ‘greens’.
- Ingredients with a lower nitrogen content (in other words a higher carbon-to-nitrogen ratio) are called ‘browns’.
Color isn’t always a reliable indicator of what is a ‘green’ or a ‘brown’ material. For example, fresh grass clippings when spread out and left to dry are still considered a ‘green’ ingredient even though they’ve turned a brownish color, because really all they’ve lost is water. On the other hand, straw is always considered a ‘brown’ because before it was cut, the main stems had died and much of the plant’s nitrogen had gone into the seeds as protein.
Good examples of greens to add to your compost pile are
grass clippings (which haven’t been sprayed with weedkiller), vegetable waste, fruit peels, annual weeds before they’ve developed seeds, and old bedding plants.
Don’t compost animal products such as meat, and try to avoid adding diseased plant material, or fats and oils.
Good examples of browns include sawdust, straw, woodchippings, shredded brown cardboard, and fallen leaves.
Bedding from herbivorous pets such as guinea pigs is ideal, as their manure adds a bit of extra nitrogen into the mix.
Compost decomposes much faster if you chop the ingredients up, so shredding woody materials and tearing up cardboard speeds up the process because there is then more surface area exposed to the microbes that decompose the compost.
However, avoid shredded evergreen trees such as Leylandii because they don’t compost well and the pine resin can inhibit seed growth.
When making compost you want to aim for 2 to 3 times more brown materials than greens, at least initially, although some more greens can be added as the compost cooks.
For most gardeners, the biggest challenge is therefore collecting enough brown materials and not just piling in loads of greens which will result in a soggy, smelly mess.
Never add lots of grass clippings in one go as they will just form a slimy matted layer.
Air is vital to the composting process so it’s important to mix the ingredients in together, and never squash them down.
By turning or remixing the compost more air is introduced, which speeds up decomposition.
The fourth vital ingredient is water. If like me you stockpile brown materials, you’ll need to water the pile to things going when first mixing it.
Build the compost pile up with layers of browns and greens, watering it where necessary to produce a moist (but not soggy) mixture.
A good compost heap has a slightly sweet composty smell. If it smells sour or rotten then it either has too many greens, or is too wet.
In either case, the remedy is to mix more brown materials in to compensate.
By getting the right balance of 2 or 3 parts browns to 1 part greens with moisture and air, you’re giving the microbes that decompose the materials the best conditions to work in.
As they break the organic matter down they give off heat, which in turns speeds up the decomposition.
In a well-mixed heap temperatures can easily reach over 150 degrees Fahrenheit, or 65 degrees Celsius.
This heap for example was mixed several days ago and it’s already been cooking nicely, although it’s starting to cool a little now.
After a few more days I will remix it to introduce more air and to bring materials from the edges into the center.
Several weeks later the heap will cool, and worms can move in to finish the process.
If you follow this recipe you should get a fine, crumbly-textured compost. Any remaining large bits can be sieved out and put into the next compost heap you build, leaving you with the very best food for your plants.