The science of organic farming is more than “farming without chemicals”. According to Australia’s organic gardening pioneer Peter Bennett, it is “a collection of skills, combined with experience and observation, which can maintain a stable life support system and produce vegetation of a high nutritional value upon which people can depend for a vigorous and healthy life-cycle”.
1. “Feed the soil, not the plant”. The foundation is the soil’s organic matter, humus and biological activity. Grazing animals transform pasture into manure, to return to the soil and become humus – essential for good soil structure and plant health. Plants need water for photosynthesis and respiration, but when water soluble chemical fertilisers are used the plant is forced to take up the fertilisers dissolved in the water, resulting in vigorous but soft, sappy growth, susceptible to pests and disease. However, when humus and the soil ecosystem are well developed organically, the vine can drink clean water, or it can absorb nutrients, as required. Deep rooted, organic vines and trees are lean but healthy and balanced, expressing the typical characters of the season, region and variety.
2. “Weeds are nature’s workers”. Rather than eradicate any plants which may “compete” with the crops and pastures, the organic approach is to see “weeds” as the builders of organic matter – the matted grass roots provide fibre, the tap roots extract deep nutrients which become available to the vines after the weeds have died and broken down. Many plants seen as “weeds” are actually “fixers” of atmospheric nitrogen as free fertiliser, or harbour beneficial insects.
Of course, noxious and declared weeds have to be eliminated by hand.
3. “Pests and diseases are the symptoms of other problems”. Fungal decomposition is part of the natural cycle in all ecosystems, and pests and disease can be seen a part of this. Rather than fighting disease with “systemic” fungicides which are absorbed into and translocated throughout the plant to kill invading diseases from the inside, the organic grower tries to avoid disease, (eg opening the canopy to air and light). Failing this, non-toxic, non-systemic products can be used, such as soap, milk, or sulfur, to help control the spread. Sanitation may help to break a disease cycle (eg burning infected canes in winter).
Similarly for insect pests – infestation may be a symptom of unhealthy plants and overuse of pesticides. By not spraying you actually encourage beneficial parasites and predators to keep the pests in natural balance.