Grape farming in Kenya has gained momentum in recent years, as farmers look to diversify their crops and capitalize on the growing demand for this flavorful fruit. However, despite their best efforts, many grape farmers in Kenya face a common challenge: their grape vines often fail to bear fruits as abundantly as desired. This has left farmers scratching their heads, wondering why their grapevines fall short of expectations. To unravel the mystery behind why grape vines tend not to bear fruits, it is essential to delve into the intricate world of grape cultivation, exploring factors such as climate, soil conditions, and the peculiarities of the grapevine itself. Only by understanding these elements can we hope to provide insights into how Kenyan grape farmers can enhance their yields and reap the rewards of this promising crop.

One of the key factors contributing to the challenge of grapevines not bearing fruits as expected in Kenya is the climate. The country’s diverse climate zones pose a significant obstacle for grape cultivation. However, Kenya’s climate can be highly variable, ranging from arid and semi-arid conditions in some areas to high rainfall in others. This variation can lead to inconsistencies in grape production, as grapevines are sensitive to temperature and moisture levels, making it crucial for farmers to select suitable grape varieties that can adapt to the local climate.

The quality of the soil plays a vital role in grapevine fruit production. Kenyan farmers must contend with varying soil types, each with its own set of challenges. For instance, grapevines prefer well-draining soils that prevent waterlogged roots, which can be detrimental to the plants. Soil fertility also plays a significant role, as grapes require specific nutrients to flourish. Soil testing and appropriate soil management practices are essential for ensuring grapevines receive the necessary nutrients and the right growing conditions.

Additionally, grapevines are known for their sensitivity to pests and diseases, which can hinder fruit production. In Kenya, pest and disease management strategies must be implemented diligently to protect grapevines from threats like powdery mildew, grape leafhoppers, and nematodes. Farmers need to stay informed about effective organic or chemical control methods and develop pest prevention plans to minimize crop damage.

In this article, we will dig deeper into these factors and explore various strategies that Kenyan grape farmers can employ to address the challenges of grapevines not bearing fruits as expected. By understanding and mitigating these issues, farmers can increase their grape yields and contribute to the growth of this emerging industry in Kenya.

Not Mature Yet

Like most fruiting plants, grapevines need to mature to at least 3 years old before they flower or fruit sufficiently. While some grapevines flower and fruit sooner, 3 years is the common expected age.

It takes this long because the grapevine’s roots and branches need to be established to gather enough nutrients, water, and sunlight to feed their flowers and fruit.

The exact length of time it takes grapevines to produce largely depends on if it was propagated from cuttings or grown from seed.

Improper Nutrients

Excess Nutrients

Too many nutrients cause grapevines to have both poor flowering and fruiting.

And there are two main reasons behind this:

Chemically burns the grapevine’s roots
High nitrogen encourages foliage growth over flowering and fruiting

Chemical fertilizers with high amounts of nitrogen will stress the grapevine’s roots. This is especially true for fertilizers that are fast-releasing. This causes the grapevine to redirect its energy from reproducing (flowering and fruiting) to surviving the burns.

Additionally, high amounts of nitrogen encourage grapevines to focus on foliage growth (as nitrogen is the main nutrient used) instead of flowering and fruiting.

Generally, compost won’t cause either of these issues as it’s not potent enough.

Lack of Nutrients

While excess nutrients affect both flowering and fruiting, a lack of nutrients more commonly affects fruit production. This is because much less energy is needed to flower than fruit.

All plants need three main nutrients: nitrogen, phosphorus, and potassium (abbreviated as NPK).

To summarize the roles of NPK:

Nitrogen is the primary nutrient, and the one responsible for foliage growth
Phosphorus is a key nutrient in flowering and fruiting
Potassium is vital to maintain the health and immune system of plants

While phosphorus is the main nutrient in flowering and fruiting, other nutrients such as potassium make it possible. So, avoid solely adding phosphorus to your grapevines.

Plants also need secondary nutrients such as magnesium, zinc, and iron.

Fortunately, most fertilizers and composts have sufficient primary and secondary nutrients. However, there are times when the grapevine’s soil could be lacking.

Soil and Fertilizer

Grapevines thrive in well-drained, rich soil. However, if the soil contains too much nitrogen, or if you’ve over-fertilized, the grapevine may put all of its energy into foliage instead of flowers and fruit. While generally a 10-10-10 balanced fertilizer is recommended for home-grown grapes, soil testing can determine the levels of nutrients in the soil and the recommended fertilizer for your soil. Adding a 4-inch layer of mulch over the rootball and watering with compost tea may be all the fertilizer your grapevine needs to produce flowers and fruit instead of only vines and leaves.

Sunlight and Pruning

Grapevines require full sun to activate the flower blossoms. Without sufficient sunlight, the flower buds won’t develop properly. In addition, pruning the vines incorrectly may affect the blossoms. Most wine grapes are pruned severely during cold season leaving only short spurs on the woody trunk and main branches. However, some grape varieties, such as “Concord,” “Crimson Seedless” and “Thompson Seedless” are cane pruned. They require longer branches, or canes, because the lowest buds may not produce fruitful vines. The non-productive vines should be trimmed back in spring and early summer to prevent them from shading the developing flower buds and blocking the sunlight, thus reducing the number of flowers produced that season.

Over-Pruning

Over-pruning grapevines result in a lack of leaves necessary for photosynthesis. Because of this, the grapevine is unable to gather a proper amount of sugar to feed itself, causing little to no flowering and fruiting. If severely over-pruned, the grapevine can die.

However, when done right, pruning can dramatically assist with fruit production.

Pruning helps to:-

Encourage more fruiting
Promote more sunlight and airflow
Manage and prevent pests and diseases
Shaping the plant into the desired appearance

Many grapevine growers prune their plant’s overlapping and excess branches to promote more and heavier fruiting. This works incredibly well as the plant has fewer branches and leaves to feed and can feed its flowers and fruits instead.

Flowers and Pollination

While most grapevines have both male and female flowers on the vine, a few species only develop male or female flowers. If your grapevine is a male riverbank grape (Vitis riparia) or muscadine (Vitis rotundifolia Michx.), its hundreds of flowers will never develop into grapes. Even grapevines that produce both male and female flowers, or have perfect flowers that contain both male and female parts, may not produce grapes if there is no wind or pollinators. Grape blossoms are mostly wind pollinated, however, varieties that require both a male and female plant require cross pollination to produce fruit. This may be accomplished by wind or bees.

Watering and Irrigation

Inconsistent or improper watering can stress the vines and affect their ability to produce fruit. Grapevines generally require deep, consistent watering during the growing season, especially during fruit development

Improper Training

Training grapevines on the wrong trellis system or not properly managing their growth can lead to reduced fruiting. Correct training and support are essential for optimal fruit production.

Pests and Diseases

Grapevines harbor a variety of pests that can affect the development of flowers and fruit. Pests such as the black vine weevil (Otiorhynchus sulcatus), branch and twig borer (Melalgus confertus), grape bud beetle (Glyptoscelis squamulata) and hoplia beetle (Hoplia callipyge) damage the leaf and flower buds. Hand picking adult borers and beetles, pruning pest-infested branches and burning the trimmings is recommended. Fungal infections such as Botrytis bunch rot (Botrytis cinerea) and powdery mildew (Erysiphe necator) also affect the buds, blossoms and developing fruit. Pruning back the grapevine’s leaves to allow air circulation and sunlight around the flowers and fruits is effective in reducing the infection.

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Why Your Grapevines Fail To Bear Fruits