If you are a wine lover, you might have heard salespeople or winemakers proclaiming some bottles to be unique thanks to high elevation vineyards. Why do they emphasize on high elevation when it comes to finished wine? Vineyards are set on high elevations because of greater temperature fluctuations, solar rays, and scarcity of water resources. High elevation grape farming is exposed to environmental limitations and challenges that help shape highly-acclaimed and unique wines. In Kenya, in Meru, Mombasa, Kibwezi, Mandera, and Naivasha, and parts of Nyeri like Othaya. are the best grape farming areas.
How Solar Rays and Temperature Affect Wine at Elevation
The acidity and tannin structure of a wine is developed in the vineyard and it’s mainly determined by the temperature shift that the vineyard sees from day to night and the exposure to the sun. The intensity and density of solar rays increase as you move upward in elevation. This means that the temperature and direct sunlight hitting the vineyard increases.
Hillside vineyards tend to receive more concentrated and direct sunlight which makes the grapefruits develop thicker skin enhancing the color concentrations and resulting in stronger tannins and flavor profiles. Greater temperature shifts between day and night are experienced in high elevation areas. When the sun sets, temperatures drop although this shift depends on the altitude. The cooler nights throughout the vineyard enable the grapes to conserve their acidity resulting in age-worthy wines. Temperature shifts also help to lengthen the growing season giving grapes more time to develop and mature on the vines. With a sloping terrain, Naivasha is one of the places where grapes can perform well. It has a warm and dry climate where grapes can receive the sun throughout the day.
Climatic conditions for growing grapes
Kenya’s climate that ranges from tropical climate to highland, arid and semi-arid climate makes it ideal for grape farming. Sufficient water, adequate sun, and heat favor viticulture. These factors are important to promote healthy growth of the vines. During fruiting, grapes require warm or hot temperatures and hence the weather must be dry and sunny. Warm temperatures increase the sugar content of the grapes.
This explains why grapes grown under irrigation in arid and semi-arid areas such as Mandera are sweeter than those from humid regions. Apart from the cool climate, Kenya has cool nights, warm days, fertile soils, and moderate rainfall which provide the optimum conditions for grape farming.
The crop thrives in well-drained soils especially in sandy and loamy soils.
Vines can be damaged by frost which happens when temperatures go below 00C. During vegetative growth, the physiological processes of grapevines begin when the temperatures are above 100C. In Kenya, the average temperatures range between 170C – 200C which are ideal for vegetative growth and flowering.
When temperatures rise above 200C, most of the physiological processes are complete and the grape clusters begin to ripen. Naivasha has temperate climates that give the vines long, warm periods which are important during flowering, fruit set, and fruit ripening.
Other factors that influence viticulture are humidity, sunlight, and wind. Grapes do not require high humidity or strong winds and perform best in places where they are put under irrigation. They thrive in places with light winds such as Naivasha and Meru.
When there is little moisture, irrigation should be ensured. However, irrigation should be withheld after heavy rains to minimize excessive vegetative growth and to force the crop to go dormant. The cropping season is from September to March. Between August and September, fruit buds should be forming and hence the plants should be kept healthy and well manured.