Soil is one of the most important components in any gardening-related practices as it dictates plant's growth rate and quality of harvest. Gardeners are reluctant to use their conventional backyard's soil as it has been generally described to have poor structure, lack in nutrients, and contain large amount of pests and diseases which can affect plants' healthy growth. At present, gardeners are substituting soil to peat as the next best alternative to conventional soil. A good 'soil' must have an open channel or structure that allows air to flow into the root networks, the ability to retain water which contains nutrients and minerals necessary for plant's growth, capacity to buffer extreme changes of acidity or alkalinity, and the absence of pests or disease-causing organisms (pathogens). All the above-mentioned characteristics of a good 'soil' can be easily found in peat (layers of accumulated partially-degraded organic matters). Recently, however, the over-harvesting of peat has resulted in the rapid decline of peatland habitats and the increased emission of carbon dioxide that will significantly contribute to the global warming phenomenon. As such, scientists have begun to formulate alternative options of 'soil' that can entirely substitute the use of peat with similar benefits but reduced environmental consequences.
1. Coir: Coir has been considered as one of the best substitute to peat due to its natural ability to retain water and several other beneficial features that may not be present in peat. Coir is usually gathered from the recycling of coconut's outer husk, a material which is usually discarded as 'waste product'. Once the husk has been cleaned to remove salts and stuck dirt particles, it is then dried, compressed, and transported for consumption. However, one major drawbacks of the usage of coir is its cost which can be twice as much as peat.
2. Bark and shredded wood fiber: These materials are light in weight and can be transported to different places with much ease. Moreover, shredded wood particulates have good water retaining capacity, and able to promote good air flow. However, the different ages of the harvested bark may affect the efficacy or usefulness of these materials as substitutes to conventional soil or peat. Some types of shredded wood fiber have the natural ability to remove nitrogen present in composts or fertilizers. Without the presence of sufficient nitrogen in its readily absorbable forms (nitrate and ammonia), plant growth will be severely affected.
3. Composted materials: Composts derived from organic waste matters, such as, coffee ground, kitchen's waste, and tea powders can help to reduce waste and promote recycling behaviors. However, many scientists believed that composts are not substitutes to peat, but rather an addition. Furthermore, poor treatments and processes of composted materials can instead bring about greater negative implications than the benefits which are initially offered.
Scientists and botanists are still looking for other 'soil' alternative that is as cheap, beneficial, and easily available as peat with minimal impacts on the environment. The quest of finding a long-term replacement to peat is an important environmental goal because over-reliance on peat will cause devastating climatic consequences as a result of increased carbon dioxide emission. Good soil is like a well-paved road; well-paved roads will not slow down or damage the cars and neither will good soil stunt nor impede plant's growth.
American Society of Agronomy (ASA), Crop Science Society of America (CSSA). "When 'soil' isn’t soil." ScienceDaily. ScienceDaily, 7 October 2015. <www.sciencedaily.com/releases/2015/10/151007185334.htm>.
W.R. Carlile, Costantino Cattivello, Patrizia Zaccheo. Organic Growing Media: Constituents and Properties. Vadose Zone Journal, 2015; 14 (6): 0 DOI