Composting And The Unsung hero: Oxygen

Transforming kitchen scraps and garden waste into nutrient-rich compost is undeniably one of the best things we can do. However the process of composting relies on an unsung hero: oxygen. You may not realize it, but getting the right amount of oxygen into the compost pile is key to breaking down compost efficiently and making great compost at home. This is known as an aerobic process.

Composting thrives in the presence of oxygen. Microorganisms, who are the unseen work force of decomposition, use oxygen during their metabolic processes to break down organic matter. This breakdown generates heat, which is essential for eliminating pathogens and weed seeds while speeding up decomposition.

All plants, trees, shrubs, agricultural crops, depend upon an aerobic environment to thrive.

How Does Aerobic Composting Work?

Aerobic composting involves the breakdown of organic material by microorganisms that need oxygen. These naturally occurring microbes reside in the moisture around the organic matter. Oxygen from the air diffuses into the moisture and is absorbed by the microbes. During aerobic digestion, the by-products are heat, water, and carbon dioxide (CO2). The heat generated in aerobic composting is enough to eliminate harmful bacteria and pathogens, as these organisms cannot survive in such conditions. It also promotes the growth of beneficial bacteria. This process also kill weeds and seeds.

Aerobic Composting has many benefits which includes:

• Efficiency and Speed: Adequate oxygen levels directly translate to fast efficient breakdown by microorganisms. This means faster composting times, allowing you to reap the rewards of your efforts sooner. In fact, you could be enjoying using your compost in as little time as 3 weeks.

  
  

• Optimal Temperature Regulation: Microbial activity naturally generates heat within the compost pile. However, excessive heat can be detrimental, killing beneficial microorganisms. Proper aeration promotes air circulation, preventing the pile from overheating and ensuring optimal temperatures for decomposition. If pile get's too hot, simply poke holes "chimneys" in the top of the pile to allow air flow. This will help to regulate the temperature of your compost pile.

  
  

• Odour Control: When oxygen is limited, the decomposition process takes a different path, becoming anaerobic. This less desirable process produces unpleasant odours, such as hydrogen sulphide, commonly known as rotten egg gas. Who wants a stinky compost bin?! We do not that's for sure. But I must admit, I was always lead to believe that if the compost is stnky it is good compost. A stinky compost bin is the opposite, not to mention that it will attract all kinds of critters who want crawl all over the pile and chow down on it. Your compost should smell good, fresh and earthy, kind of like the fresh smell of a forest.

Anaerobic compost will have a white ash on it. This is because there is because all the oxygen has been used up. Plant pathogens, weed and seeds are not able to be killed under anaerobic conditions as they thrive in that environment.

What is Anaerobic Composting?

Anaerobic composting is decomposition that occurs using microorganisms that do not require oxygen to survive. In an anaerobic system the majority of the chemical energy contained within the starting material is released as methane. The process is characterised by very strong odors and only a small amount of heat is generated meaning decomposition takes much longer and doesn’t reach sufficient temperatures to safely kill plant pathogens, weed and seeds. To overcome these limitations external (artificial) heat is normally added.

What's the Connection with Soil Health?

Aerating your compost is the optimal approach because the end result boosts the soil with nutrients and structure. The organic matter in the soil helps form stable soil clumps, which boost soil porosity and make it more resistant to being washed or blown away, which reduces soil erosion and compaction. Better soil porosity and lower bulk density make it easier for water to seep in, move through, and keep the soil aerated, helping the soil soak up and hold more water, and giving roots and soil organisms room to grow and breathe.

This also helps with the soil's chemistry, keeping the pH stable and adding nutrients to boost soil fertility. Compost is packed with key plant nutrients like nitrogen (N), phosphorus (P), and potassium (K). These nutrients are mostly released slowly and organically, which means they're less likely to wash away and pollute water bodies compared to chemical fertilizers. Using compost helps the soil hang onto nutrients and keeps the pH close to neutral, making nutrients more available to plants.

Compost also ups the organic carbon in soils by directly adding carbon and by boosting plant growth, which adds more carbon through roots and leftovers.

What about Plant Pathogens, Weeds and Seeds?

In order to reduce and eliminate plant pathogens, weeds and seeds in your compost pile, temperatures must remain at 131 degrees Fahrenheit or above (maximum 160 degrees Fahrenheit) for several days. The exact amount of time depends on the method of composting and the temperature that your piles get to. Controlling the oxygen, moisture, pile structure, and nutrient balance, helps achieve the optimal temperature range in a compost pile. Once the pile returns to ambient temperatures, it needs a little time to mature. When aerated composting methosds are used, your compost is ready to be put to work in your home vegetable garden with in 2 - 3 weeks verses months or even years with some methods.

A thermometer is needed for aerobic composting to ensure that the adequate temperatures are maintained for the composting process.

In order to have really good compost, you need three things: food source, water and oxygen. Yet the unsung hero in the composting equation is, with out the shadow of a doubt, oxygen. By turning the pile, blowing air into the pile through pipes or vents, creating chimneys if needed, as well as adding bulking agents such as wood chips and dry leaves to the pile all help to increase aeration.

Ultimately, when applying aerating compost methods, you end up with superior compost is great for soil biology by increasing the variety and number of helpful soil organisms, which munch on soil organic carbon and make nutrients available for plants. This method of composting also helps to eliminate weed seeds and plant pathogens, which makes this method of composting a winner for our garden!

We invite you to consider trying aerobic composting this growing season.

Happy Gardening!