An Integrated Fertiliser Strategy for Kitchen Garden

“Go organic” is the mantra these days especially for home-grown vegetables. Organic model advocates using organic pesticides and fertilisers for farming, and prohibits use of any inorganic (chemical) pesticide or fertiliser.

Organic farming is the methodology for future; it is the best for health of consumers and health of soil ecosystem. While total organic model is the right one for commercial or large scale farming, there can be a modified approach for home kitchen gardens, especially when plants are grown in containers (pots or polythene bags).

While discussing organic vs inorganic farming, two entirely distinct elements need to be considered: (1) use of inorganic vs organic pesticides to control pests and diseases, and (2) use of inorganic vs organic fertilisers for improved growth and yield.

(1) Use of inorganic vs organic pesticides
When inorganic pesticides are used in farming, agricultural produces may contain residues of pesticides. This is a health hazard, and so use of inorganic pesticides at any stage of farming process is a strict NO.

(2) Use of inorganic vs organic fertilisers
Plants absorb nutrients contained in fertilisers through “osmosis” process, and fertilisers are to be in water-soluble (mineral) form in order for this process to happen. This is true whether the fertiliser is organic or inorganic. In case of inorganic fertilisers, nutrients are already in mineral form, and are readily absorbable by plants. This accounts for faster release and absorption of inorganic fertilisers by the plants. In the case of organic fertilisers, converting constituent nutrients in organic fertilisers into their equivalents in mineral form is done by micro-organisms in the soil. Inorganic fertilisers have the downside that they kill micro-organisms in the soil causing impairment of soil ecosystem and environmental damage in the long term, whereas organic fertilisers stabilise and improve soil structure.

Mineral nutrients, whether sourced from inorganic or organic fertilisers, are exactly in the same form when they are absorbed by the plants. It may be possible to identity the type/source of the fertiliser (whether organic or inorganic) in laboratory testing, but does vegetables grown with inorganic fertilisers cause any health issues? So far all talk has been only about health hazards caused by inorganic pesticides, and not about inorganic fertilisers. Of course, one is not talking about excessive use of inorganic fertilisers, or health hazards if they are not handled properly.

The point is that while use of inorganic pesticides causes health hazards for consumers of agricultural produce, use of inorganic fertilisers does not cause health hazard for the humans, but for the soil ecosystem. If inorganic fertilisers do not pose a health hazard to humans, why not use them in the farming?

A practical strategy could be using a mix of both types of fertilisers. The containers (pots or bags) can be filled initially (then replenished from time to time) with organic fertilisers. In addition, moderate quantities of right types of inorganic fertilisers can be given at appropriate times to accelerate growth and improve yield. The soil in the container is usually discarded after every growth season, and replaced with new soil mix. Micro-organisms in the discarded soil may have been destroyed, however the volume of this soil is so small to cause any significant ecological impact.

Even when kitchen vegetables are grown on the ground, considering that the garden area is usually very small, a mix of organic cum inorganic fertiliser usage can practiced. The environmental damage caused by inorganic fertilisers can be compensated by ample use of soil stabilisers, such as compost.

The common belief that the vegetables grown with organic fertilisers tastes better than the ones grown with inorganic fertilisers could be a myth and more of a psychological conviction. The vegetables plucked from the kitchen garden could be tastier for other reasons too. Store-bought vegetables cannot be as fresh as the plant-to-pan ones from the kitchen garden. It is also possible that the store vegetables are plucked before ripening to increase shelf life, and are placed on the shelf after having withstood storage and transportation stress.

To summarise, an integrated fertiliser strategy for kitchen garden farming could be non-use of inorganic pesticides, and use of organic fertilisers as primary source, augmented by moderate use of inorganic fertilisers, especially when the plants are grown in containers.