The mention of Hawaiian agriculture tends to invoke images of large cattle ranches and fields of sugar cane and pineapples. However, Hawaii’s rich soil and climatic variation make it home to a wide variety of plant species. Although greenhouse and nursery plants are the most prominent agricultural commodities, nuts, coffee, and tropical fruits all significantly contribute to the $661.3 million economic impact of Hawaiian agriculture. In order to sustain the life of Hawaii’s 7,000 farms and 97 farmers markets, it is essential that farms like Ginger Hill work to enrich the Hawaiian soil in a sustainable manner.
The Basics of Composting
Ginger Hill preserves the integrity of its soil and the nutrition of its plants by composting. The product of composting is, of course, compost, or decomposed organic matter, and it is used to enrich the soil in which we grow our plants. In nature, insects and bacteria consume dead vegetation, leaving behind particles called humus. Humus, in turn, binds soil particles, allowing water and air permeate the soil with ease. This process of aerobic respiration yields nutrients like nitrogen, phosphorus, and potassium that enrich the decomposed matter, as well as beneficial microorganisms that out-compete bad pathogens. Composting is a form of recycling organic farm waste that mimics and accelerates the natural decomposition of organic matter into soil.
We decided it was time to build a new compost pile at Ginger Hill in late October. We compost in the interest of making Hawaiian agriculture more sustainable, fruitful, and cost-effective. To begin, we established a layer of dry, brown leaves and wood chips to provide the pile with a source of carbon. We then added a green layer of leaves from Ti plants and chestnut trees to contribute nitrogen. Finally, we continued to alternate layers of carbon (brown) and nitrogen (green)-containing materials until the pile was approximately four feet tall.
Carbon and nitrogen are the essential components of compost. Carbon generates energy for microorganisms and nitrogen synthesizes necessary proteins. An excess of carbon in the pile will decrease the rate of organic decomposition. An excess of nitrogen produces smelly, slimy compost that does not break down efficiently, especially when moisture levels are too high or the matter is packed too densely. By creating alternating layers of nitrogen and carbon, periodically adding water, we were able to create a pile with an optimal moisture level and balance of nitrogen and carbon.
Composting “Hacks”: Comfrey and Manure
Two of our nitrogen layers were comprised solely of the comfrey plant, a powerhouse in Hawaiian agriculture. Comfrey has roots that extend deep into the ground, extracting nutrients from the subsoil. As the harvested comfrey activates the compost pile and begins to break down, its nutrients permeate the pile. Utilizing comfrey for composting thus ensures that our compost is optimally rich in nutrients.
The more densely the compost pile is populated with microorganisms, the more efficiently the compost will break down. In order to increase the microorganism population of our compost, we add pig manure from our own pigs. Using pig manure, we are able to create compost that breaks down completely in three to six months.
In the coming weeks, we will need to “turn” the pile. Turning the pile aerates it, providing necessary oxygen to the microorganisms working to break down the organic matter. If created properly, the compost will naturally aerate to some degree. Using shredded brown material, such as our leaves and wood chips, improves aeration and moisture distribution. However, manual aeration will greatly enhance the efficiency and productivity of the decomposition process.
The Benefits of Composting for Hawaiian Agriculture
Composting is incredibly beneficial, especially for a process that took a mere three hours for three people to complete. By composting, we ensure that the organic matter on our farm re-enters the lifecycle, enriching our gardens instead of going to waste. Creating compost is economically sensible as well, eliminating soil and fertilizer expenditures. The nutrient density of compost significantly enriches the soil, which, in turn, enhances the health of our plants. Using compost helps us to grow plants that can better defend against the detriments of pests and disease. It also allows us to increase the nutrient-density of our food and thus improve the health of our bodies. Finally, composting enriches the bed of soil already existing underneath of the pile, creating an excellent site for future plant growth.
We live in an era where corporate interests often compromise the health of our environment and our food. It is estimated that 1/3 of landfill waste is comprised of compostable material. Hawaii residents are particularly culpable in the waste problem, as the average Hawaii resident produces more than twice as much waste per day as the average mainland resident. Tourism and the necessity of importation are likely contributors to Hawaii’s waste problem. Composting is an excellent method of reducing the waste produced by Hawaiian agriculture. It also allows us to grow more nutritious plants, offsetting the negative impact of heavily processed food.
There are other forms of composting and recycling that we use at Ginger Hill. We use ash from our community bonfires as fertilizer; we create compost from kitchen waste, including fruits, vegetables, coffee grounds, and eggshells; and we feed food scraps to our pigs. We believe that Hawaiian agriculture has a significant role to play in improving Hawaii’s waste problem, and we try every day to do our part.