Another large factor in B.C. is the drop in temperature that occurs for the last several weeks prior to harvest. This stimulates all of the biological systems that we accept as occurring prior to harvest. Our experience in B.C. with grape varieties suited to Coastal or Interior viticulture has demonstrated that short-season Coastal varieties lack character when grown in the Interior but longer season Interior varieties often fail to ripen at the Coast. In a region with uniform temperature year round, variety selection to minimize cool temperature dependence may be critical to ripening the crop in spite of unlimited season length.


Timing of rainfall can be critical to successful viticulture. In arid or semi- arid regions, rainfall is seldom a problem so long as irrigation is available. There are critical periods such as bloom and harvest when rainfall can be a serious problem. If an equatorial region has a monsoon season, it may be a good idea to avoid bloom or harvest at that time. Equatorial regions have the advantage that the growing season can be initiated at any time by pruning the vines or defoliating them.


To choose season initiation, just count backwards about three months from the monsoon season and bloom should be complete before it rains. The heavy rains can then be helpful to develop the crop. The dry period after the monsoon should help to develop the crop with good character and a balanced composition. Irrigate only if absolutely required. In a region with moderate rainfall instead of monsoons, equatorial regions can ripen multiple crops per year. The yield may be slightly lower than with temperate region viticulture but the multiple crops compensate. Some table grape varieties adapt by setting fruit throughout the year, and essentially become ever bearing. It may be tricky to commercialize ever-bearing grape vines when you have simultaneous clusters at all stages of ripeness. The final factor I must address is temperature. The stomata of grapes tend to close at about 40C. Some are more tolerant of high temperature than others. To keep vineyard temperature in a more optimal range, the best solution at the equator is to


British Columbia FRUIT GROWER • Winter 2016-17 19 GARY STRACHAN A view of Naramata's vineyards in early winter from Summerland.


establish the vineyard at a higher altitude. If an east facing slope is available to avoid direct afternoon sun, so much the better. Other factors such as birds and animals will always plague grape growers, but the good news is that grapes are not native to equatorial regions and unless diseases are imported, there should be less


requirement for regular sprays. The requirement will have to be based on trials when vineyards move into a new region.


I asked a Colombian farmer if he could provide me with a high-altitude site with an east-facing slope and he said “No problem”.


I’m not sure about the “No problem” bit.


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