Growing wine grapes in a tropical climate with double pruning

Why tropical vineyards need a different calendar

In Europe a vine rests through a cold winter, buds in spring, flowers in early summer and is harvested in autumn. Cold dormancy resets the vine each year.

Indian wine regions such as Nashik and Pune in Maharashtra and the areas around Bengaluru and Vijayapura in Karnataka sit in the tropics or close to them. There is no real winter dormancy. Left alone, a vine would grow almost continuously. Worse, the natural ripening time would fall in the monsoon, when rain swells berries, dilutes flavour and spreads fungal disease.

Double pruning solves both problems. It forces the vine into two cycles a year and times the fruiting cycle so the grapes ripen in the dry season. Our guide to Indian wine regions covers where these vineyards are.

The first cut: back pruning

After harvest, typically around March or April, growers carry out back pruning, sometimes called foundation pruning. Canes are cut back hard to a couple of buds.

The vine then grows through the hot months and the monsoon. This cycle is not for fruit. Its job is to build strong canes and store carbohydrate in the wood. Any bunches that form are usually removed. Leaving them would drain the vine and ripen fruit straight into the monsoon rain. Good canopy management in this period decides how fruitful the next season will be, because the buds that carry next season's bunches form now.

The second cut: fruit pruning

Once the monsoon eases, usually around September or October, growers do the fruit pruning, also called forward pruning. Canes are cut to a length that leaves fruitful buds.

Without a cold winter, buds can break unevenly. Many Indian growers apply a bud-break agent such as hydrogen cyanamide to the buds after pruning to get even growth. This is a regulated agrochemical and is applied under agronomist guidance, with strict safety precautions.

The vine then flowers, sets fruit and ripens through the cool, dry winter. Harvest for wine grapes usually falls from January to March, depending on region and variety.

What this means for the wine

Ripening in the dry winter gives Indian growers clear advantages. Days are sunny and nights are cooler, which helps keep acidity. Disease pressure is far lower than it would be in the monsoon.

There are trade-offs. The ripening window is short and ends as temperatures climb sharply in March. Late varieties can struggle to reach full flavour ripeness before the heat arrives. Sugar can race ahead of flavour and acid can drop fast. Picking dates are often a careful balance between sugar, acid and the weather forecast. Our guide to wine harvest and vintage planning describes how wineries plan around that window.

This is one reason Sauvignon Blanc, Chenin Blanc and Shiraz have done well in India. They can be picked fresh before the heat arrives. Our grape varieties guide describes them.

Weather risks in the fruiting season

The dry season is not risk-free. Unseasonal rain or hail in February or March can split berries close to harvest and invite rot. A warm spell can push sugar up faster than the winery can receive fruit. Fog and dew in early winter can raise mildew pressure.

Birds and wasps also arrive as berries soften. Netting is common in smaller blocks. Growers watch forecasts closely in this period. Wineries need a plan for receiving fruit early or late, because a sudden change in weather can move picking by a week or more.

What winemakers should ask growers

• When was fruit pruning done for each block? That sets the expected harvest window.
• How even was bud break? Uneven bud break means uneven ripeness in the same block.
• What crop load is the grower aiming for? Heavy crops ripen more slowly and the window is short.
• What sprays were used and when? Residues and pre-harvest intervals matter for fermentation and food safety.
• How will rain near harvest be handled?

Winemaking in India starts with understanding this calendar. A winemaker who knows when and why the vines were cut can plan fermentation capacity, yeast and staffing far better than one who waits for the trucks to arrive.