Irrigation is a potentially divisive issue in wine–growing and agriculture in general, purists arguing dry farming should be mandatory, versus those who fail ‘to discern any logical distinction between rainfall and water applied by hoses or sprinklers, provided it is done within reason and at the right time (i.e. not shortly before the harvest (Hugh Johnson: Wine Companion 1991, p.15) See also water.

Don’t waste water: ‘Much [irrigation water] is wasted. “Flood” irrigation systems, where water is released to inundate fields or furrows, lose water to evaporation, or to percolation (ie, to the soil itself before it can be absorbed by the crop’s roots). A common estimate is that flood-irrigation squanders 50% of the water it releases.

Sprinkler systems can help with efficiency. But these, too, are imprecise, vulnerable to the wind and to loss of water through evaporation. Far more effective are “drip” irrigation systems introduced in Israel in the 1960s. As the name suggests, these direct limited amounts of water to the plants themselves, so that they get enough but not too much. Avi Schweitzer, chief technology officer of Netafim, an Israeli company that sells drip-irrigation equipment and technology in 110 countries, says that, by minimising both evaporation and percolation, it manages to achieve 95-97% efficiency in delivering the water to the photosynthetic process,’ (The Economist, Special Report on Water, March 2nd 2019).

Numbers: ‘It takes 2,000 litres (530 American gallons) of water to grow a kilo (2.2lb) of vegetables but 15,000 litres to produce a kilo of beef-and people are eating more meat…Agriculture uses three-quarters of the world’s water,’ (The Economist 11th April 2009, p.17). ‘It takes more that four litres of water to produce an almond,’ (‘The new Anthrpocene diet’, The Economist 2nd October 2021, p.5).

When to irrigate: Peter Proctor (Grasp the Nettle, p.116) says ‘you should not generally need to irrigate plants growing in soil that has been biodynamically managed and so has a reasonable humus content and good structure, as their roots penetrate deep into the soil. Remember that irrigating during a hot period will intensify the breakdown of the all-important humus, and will also bring the roots to the surface of the soil. Consequently the plants will then need more irrigation. Much of the irrigation water used in the heat of the day will evaporate and be lost to the immediate water circulatory system.’

Disadvantages of drip Irrigation: ‘One thing I can state unequivocally: The pernicious practice of drip irrigation, as it is used in California, essentially infantilizes plants, turning them into dumb, sterile consumers, as if they were grown in flowerpots, making them gatherers rather than hunters…[which] essentially negates the possibility of the expression of terroir,’ Randall Grahm suggests (‘The Phenomenology of Terroir: A Meditation’, World of Fine Wine 13 2006, p.102-107).