Increasing numbers of home gardeners are turning against chemical fertilizers as the main means of feeding their garden plants. This trend is strengthened by the vague idea that chemical fertilizers are synthetic products and therefore unnatural.
When it comes to growing edible plants, many people believe that they and their families are consuming unhealthy synthetic residues as opposed to “pure” fruit and vegetables that have been grown organically. There are some excellent reasons for not applying chemical fertilizers, but the above objections are largely mythical.
The real distinction however is not between “natural” and “artificial”, but between plant food that is mineral in form, (i.e. chemical fertilizer) and that which is organic (compost, worm castings e.t.c.). Moreover, plants absorb essential nutrients as mineral salts dissolved in the soil water, and so the elements present in organic matter have to break down to an inorganic, mineral state before being available to the plants.
What is Chemical Fertilizer
Chemical fertilizing is a method of directly supplying the elements such as Nitrogen and Potassium, which are essential to plant growth and development. Chemical fertilizing simply bypasses the process by which matter breaks down from an organic state to a mineral one. Providing that quantities are appropriate, there is nothing necessarily abnormal about the plants’ makeup.
Common fertilizers like Ammonium Sulphate, Potassium Chloride, or Potash, should not be confused with synthetic pesticides, which are indeed poisons whose residues are liable to be present in the edible plants that have been treated with them. Organically grown produce will of course be free of pesticide residues, this being the primary reason for preferring it from a health point of view. Yet there are perfectly valid reasons for objecting to the use of chemical fertilizers. These have far less to do with their direct effects on the plants, but rather in the indirect, cumulative consequences for the soil and the environment.
Negative Effects on the Soil
Consistent and perpetual application of chemical fertilizer degrades the physical structure of the soil, leading to a lack of oxygen in the plants’ root zone. A number of processes are responsible for this, such as increasing soil salinity, alkalinity, and sodium levels. All can be traced back to the long-term use of chemical fertilizers, and are especially dangerous in dry climates.
Feeding the plants indirectly, by means of organic matter on the other hand, enhances the chemical, physical, and biological health of the soil. Ultimately, the quality of the garden plants is only as good as the quality of the soil in which they grow.
Chemical fertilizers, especially nitrogen and phosphorus ones are a serious form of pollution, as the excess leaches into lakes, rivers and the water table. Chemical reactions transform the nitrogen into nitrites and nitrates that are wreaking havoc with natural eco-systems. In this respect though, commercial composts based on manure, are also pollutants, albeit at a much reduced level. From an environmental angle therefore, it is better to use plant-based composts.