Viticulture is a Latin word for vine. It’s the science, production, and study of grapes.
It deals with the series of events that occur in the vineyard. Viticulture has been practiced all over the world especially in developed countries with majority of production being for wineries.
Central Valley Vineyard
Grape Varieties
There are very two main grape varieties being Table variety and Wine variety. The grapes are either seedless or seeded. There are over 1300 species of grapes depending on country origin and cultivar propagation.
The cultivars can either be Red grapes, White grapes, Rose grapes and Purple/Pink grapes that can either be propagated for table or wine production.
Major Wine varieties are:
Cabernet Sauvignon
Chardonnay
Pinot Noir
Sauvignon Blanc Major Red Table varieties are:
Flame Seedless
Swenson Red
Red Globe
Ruby Seedless
Christmas Rose
Emperor
Crimson Seedless
Major White Grapes varieties:
Thompson Seedless
Perlette
Sugraone
Niagara
Cabernet Franc
Pinot Gris
Shiraz
Chenin Blanc
Tudor Premium Red
Scarlet Royal
Cardinal
Delaware
Ruby Roman
Vintage Red
Muscat of Alexandria
Italia
Autumn King
Princess
Cotton Candy
Other varieties – Blue/Black/Purple Grapes:
Beauty Seedless
Concord
Muscat of Hamburg
Muscat of Alexandria
Autumn Royal
Fantasy Seedless
Climatic Conditions
Alphonse
Marroo
Niabell
Summer Royal
Pione
Kenya’s diverse climate from tropical coastal equatorial climate to arid and semi- arid climate and highland climate makes it ideal for Grapes. The presence of adequate sun, heat and water makes it ideal for viticulture. These factors are all vital to ensure healthy growth and development of grapevines during the growing season.
Additionally, continuing research has shed more light on the influence of dormancy that occurs after harvest when the grapevine essentially shuts down and reserves its energy for the beginning of the next year's growing cycle. In general, grapevines thrive in temperate climates which grant the vines long, warm periods during the crucial flowering, fruit set and ripening periods.
The physiological processes of a lot of grapevines begin when temperatures reach around 10 °C.
Below this temperature, the vines are usually in a period of dormancy. Vines can be damaged by frost if temperatures go below 0 °C. Kenya’s average temperatures range between 17 and 20 °C which enables the vines to start flowering. When temperatures rise to 27 °C (80 °F) many of the vine's physiological processes are in full stride as grape clusters begin to ripen.
One of the characteristics that differentiates the various climate categories from one another is the occurrence and length of time that these optimal temperatures appear during the growing season.
Other climate factors such as wind, humidity, atmospheric pressure, sunlight can also have pronounced influences on the viticulture of an area.
Grapes Maturity Period
This topic covers duration of maturity from propagation/planting to the first harvest.
Grapes are majorly propagated using cuttings and by grafting which is preferred because they produce vines identical to the parent in characteristics.
However, the maturity period is highly dependent on management practices since planting. These include, pruning, fertilizer/manure application, watering, disease & pest control, environmental factors and soil drainage.
Planting & Spacing
This topic covers spacing requirements and how spacing affect production and management practices in the vineyard.
For table grapes and wine grapes require different spacing.
Soil Type, Soil PH & Topography
Grapes grow in a wide array of soils, they best perform on deep and well drained soils with soil depth of 1-2 meters.
In viticulture, one should avoid heavy clay soils, the soils must not have a high concentration of salts, and should also avoid very shallow and poorly drained soils.
This topic covers the required PH levels for grapes, and why topography is important for prevention of diseases and other related factors that affect production.
Soil Fertility
Both fertilizers and organic matter are fine depending on the nutrient requirement and their dissolution rate.
Grapes do not have a lot of fertilizer requirements. This topic will cover only the necessary components that are required at what stage and in what quantities.
Grapevine Management
Disease & Pest Control
There are two serious fungal diseases that affect grapes, and this topic will discuss them and any other likely diseases that can affect grapes.
Powdery Mildew Causes
This will topic will explain the causal factors of Powdery mildew and how to spot it in the vineyard.
Control & Prevention
This topic will discuss how to control and prevent the disease including the pre- infection and post-infection fungicides to use for both scenarios.
Downy Mildew Causes
This will topic will explain the causal factors of Powdery mildew and how to spot it in the vineyard.
Control & Prevention
This topic will discuss how to control and prevent the disease including the pre- infection and post-infection fungicides to use for both scenarios.
It will also discuss the recommended fungicides since some have a certain post- harvest Interval (PHI) that should be met
Botrytis Bunch Rot (Gray Mold)
Botrytis bunch rot also known as Gray mold of grape, is one of the most important diseases of grapes in the world, which can cause serious losses in grape yields.
Symptoms
What are the symptoms to look out for, for Botrytis and what are the conditions that favor the growth of this fungus.
Control & Prevention
This topic will cover how to prevent and control it both for the current crop and for future crops.
Pests
Grapes do not have many pests that affect them, however if the vineyard is next or near untrimmed and tall hedges and bushes, this may attract certain pests that can destroy your vines and fruits.
It will cover how to keep them away and protect your vineyard.
Watering/Irrigation
This topic will cover water requirement in terms of quantity and frequency and the factors that will determine the irrigation methods and types to use.
It will also cover water requirements at different stages of growth of the vines.
Pruning & Training
The Grapevine is a true vine that requires some form of support to keep it off the ground.
This is perhaps the most important management practice for grapes that determine the yield per season.
Pruning can be defined as the removal of plant parts to obtain horticultural objectives. This will cover the objectives of pruning.
Training can be defined as the arrangement of plant parts spatially. Why is it done and which are the training systems to use?
Vine Morphology
It details the structure of the vines at each growth stages in the lifecycle of a vineyard.
How the vine should be managed during:
First Year Training options
First Dormant pruning
Second Year Training options
Second Dormant pruning
Third Year growing season
Training & Trellis
Training systems
There are two types of training systems, Low Cordon and High Cordon training systems. Which should be used for which variety and why?
Low Cordon (Upward growth)
This system is suitable for which cultivars?
Low Cordon (Downward growth)
This system is suitable for which cultivars?
Installation of Trellis Support System
This phase is one of the most resource intensive exercise. It involves installation of support for the vines.
This topic will cover the specifications for a good trellis system
When should the vines be trained
Why and when should the vines be trained, and how does this affect production.
Canopy Management
Canopy Management is the balance between Clusters available and vegetative growth required to mature the clusters. Why is the balance important?
Shoot Positioning
Why is shoot positioning important and how does it affect production?
Shoot Trimming
Why is shoot trimming important and how does it affect production?
Grapevine Production
Fruiting & Harvesting
Cluster Thinning
Cluster thinning is one of the most important cultural practices early in flowering. Why is done and what are the factors that affect cluster thinning?
Checking for Ripening
How do you check for veraison or ripening? Different varieties are checked differently and show different signs.
Production
What should be the average production per acre? This figure however is largely dependent on many factors including, cultural management practices, watering, variety planted, vine spacing, climatic conditions, protection of fruit, etc.
One ton of grapes yields about 60 cases or 720 bottles of wine.
Storage and Packaging
While harvesting, it’s advisable to have crates as the temporary collection and storage equipment.
Crates ensure that grape clusters do not press hard against each other which may lead to destruction of the quality of the end product.
The crates should then be transported carefully to the selection or winery for processing.
If the end product is Table grape, packaging can be done in punnets that are used for retailing the fruits. The punnets can then be packaged into cartons for transportation.
Other Vineyard Management Practices
During fruiting and as the clusters continue to mature, this is one of the best moments as one can see the fruits of their hard work.
However, all is not rosy as there are others eyeing your juicy grapes as they ripen and turn color. One of the major enemies of grapes is birds. Birds should be controlled by all means as they can significantly reduce your grape yields by eating the fruits. There are many ways of scaring birds away such as scare crows, bird netting, physical deterrence, propane shoots, etc.
Market for Grapes
The demand for locally grown fresh grapes is far from being met both for table and wine. Over 99% of table grapes consumed locally are imported from South Africa and Egypt mainly. These countries have many hectares under vineyard due to their established wine production. Kenya is therefore very ripe for growing and producing grapes locally to meet the demand and make the fruits and wines affordable.
A lot of imported wine is very expensive and beyond the reach of many Kenyans who are wine lovers. A kilo of imported Grapes in the local retail market goes for between Ksh 500 and 800. Kenya has the capacity to set up vineyards for production of table and wine grapes. Some farmers in Dodoma, Tanzania have been growing grapes for wine production and the wine is consumed in Tanzania.
There are currently only two commercial wineries in Kenya that produce wine for consumption. One of them imports fresh grapes for making wine since they are unable to produce enough grapes to meet their demand for wine.
In conclusion, the demand is very high and the local supply is almost zero, someone must start filling in the gap and the benefits are outright.
There is very little or no competition at all among farmers since few grow the crop.
Labor Requirements
A Vineyard requires careful, constant and present monitoring due to high susceptibility of the vines to the diseases discussed earlier.
Therefore, having workers on site permanently is not an option.
From a few vines to several acres, the vineyard must be tended to nearly daily. Some of the activities frequently done include:
Spraying
Weeding/hedge trimming
Supporting/trellising
Fruit protection
Watering
Pruning and Training
Canopy management
All these activities require human labor or machinery to carry out, and therefore reliable and present labor must be provided.
Challenges
Like any other farming activity, grapes farming has its own challenges, some unique and others common. Some of the challenges one might encounter include:
Disease control and
Abrupt change of weather affects grapes and this can encourage
Water availability must be
Workers must be willing to stay on site
Since few farmers grow grapes, some of the challenges encountered might be unique and therefore getting help might be a
The government through KARI/KARLO has not invested well in grapes and therefore there are no extension
After harvesting, the fruits must be refrigerated to preserve them if they are for table
Vineyard establishment is expensive due to all the inputs required, both capital and
Finally, not many farmers are willing to wait for over 1.5 years since planting till the first harvest it takes patience.
For more information contact Central Valley Vineyards
Additionally, continuing research has shed more light on the influence of dormancy that occurs after harvest when the grapevine essentially shuts down and reserves its energy for the beginning of the next year's growing cycle. In general, grapevines thrive in temperate climates which grant the vines long, warm periods during the crucial flowering, fruit set and ripening periods.
The physiological processes of a lot of grapevines begin when temperatures reach around 10 °C.
Below this temperature, the vines are usually in a period of dormancy. Vines can be damaged by frost if temperatures go below 0 °C. Kenya’s average temperatures range between 17 and 20 °C which enables the vines to start flowering. When temperatures rise to 27 °C (80 °F) many of the vine's physiological processes are in full stride as grape clusters begin to ripen.
One of the characteristics that differentiates the various climate categories from one another is the occurrence and length of time that these optimal temperatures appear during the growing season.
Other climate factors such as wind, humidity, atmospheric pressure, sunlight can also have pronounced influences on the viticulture of an area.
However, all is not rosy as there are others eyeing your juicy grapes as they ripen and turn color. One of the major enemies of grapes is birds. Birds should be controlled by all means as they can significantly reduce your grape yields by eating the fruits. There are many ways of scaring birds away such as scare crows, bird netting, physical deterrence, propane shoots, etc.
