How to start composting

Growing a healthy food garden that supplies you all your known essential nutrients requires giving the plants all their essential nutrients too! Whether you are living in a urban home, suburban property, off grid or are not even creating a food garden but a decorative garden instead, composting is an easy and resourceful way to improve soil quality and help keep your plants healthy.

What may seem like a huge project to get started is actually very simple. The biggest barrier to getting started is quite possibly just one’s own mind!

What does one need to start composting?

• A composting bin, container, ditch or even just a place to make a pile!
• “Green” material - for example fruit scraps, vegetable scraps, grass clippings, tea, coffee grounds, egg shells, green leaves, old flowers
• “Brown” material - for example plant cuttings, (untreated) woodchips and sawdust, paper, straw, cardboard, dry leaves

That’s it!

How to compost?

The composting process depends on factors including:

• Mixture, or layers, of brown and green material (brown material supplies a lot of carbon and green material supplies a lot of nitrogen)
• Moisture
• Oxygen
• Microorganisms
• Temperature

Brown and green material

Start with a layer of dry leaves, bush or tree cuttings or other “brown” material at the bottom of your compost bin or heap. This helps with aeration. Then layer ”green” material on top and continue to alternate the following layers. One can alternatively just add the materials as they become available while maintaining proper proportions.¹

It is suggested a carbon:nitrogen ratio of 30:1 is optimal for fast aerobic decomposition,^1,2,3 but this doesn’t mean 30 parts brown material to 1 part green material. Green material and brown material both contain carbon and nitrogen, just in different proportions. So, roughly a ratio of 2-3 parts brown to 1 part green can be used to make compost.¹ The exact proportion of green to brown material isn’t something to worry too much about, just keep an eye on how it looks and smells. When it is smelling sweet and earthy you know it is processing well. Too much carbon will make the composting process take longer and too much nitrogen will increase loss of nitrogen via ammonia (and cause a bad smell).^1,2

Keeping material as small as possible will quicken the process by increasing the surface area exposed to the microorganisms and reactants.

Moisture

Ensure the pile is wet enough - damp but not saturated! It might be wet enough through the addition of items like moist fruit and vegetable scraps. If not, wet the pile with water. Being too dry will slow down the compost heap’s decomposition. Keeping it out of the sun can prevent it drying out. Too much moisture can prevent oxygen from circulating through the compost pile and also slow down decomposition.^1,2

Oxygen

Aerate the pile to maintain aerobic decay by microorganisms. Anearobic decay (decay that occurs without oxygen) takes longer and releases smelly odours.^1,2 This can be done with a well designed compost bin that maintains airflow or by manually turning the material.

Microorganims

There are many microorganisms involved in the aerobic decomposition of material in a compost heap, including bacteria and fungi species. Their populations change over the course of the decomposing process. Some are more abundant when the compost heap is at a moderate temperature and others start proliferating when the temperature increases to 40-70ºC. During anearobic decompostion (when there is limited oxygen supply) there are different organisms again. These microorganisms use nitrogen and carbon in the green and brown material, oxygen and other molecules for their metabolic processes that lead to the decomposition of the matter.^1,2,4

Temperature

The pile will naturally increase in temperature as the decomposing process occurs and return to ambient temperature when it is finished.¹ Thus, the temperature depends on the previous factors.

Composition of the final product

Through the composting process the recycling of nutrients occurs, making them available to the surrounding environment and to your plants. The final compost product, however, is said not to be a complete source of the essential nutrients that plants need in their soil.⁴ This is due to the fact that the starting materials may be low in some nutrients to begin with and that nutrients can be lost through the decomposing process.^1,2,5

The quality of the end product depends, in part, on the quality of the material going into the composting pile. There are many proposed methods for increasing the nutrient value of compost that go beyond the scope of this post.

Compost does improve soil structure, allow for nutrient mobilization, increase soil fertility and supply many nutrients though.⁴

By keeping an eye on all the above factors, one can reduce the nutrient loss in your compost and produce a richer final product in the smallest possible time frame. Depending on the conditions, compost can ready in a period of weeks to months.³

References