Flower and fruit drop is a common problem that gardeners often face. This phenomenon can lead to a significant reduction in the harvest of vegetables and fruits and sometimes even to its complete loss. To avoid this in the future, you need to understand the causes.
Fruit drop can be caused by many factors: sudden temperature changes, improper watering, lack of fertilization, and more. Let's break it down step by step.
Causes of fruit drop
One of the main reasons lies in the violation of growing conditions (whether due to the gardener or nature’s whims). Each plant has its own requirements for light, temperature, humidity, and nutrition. If these parameters are not met, the fruits stop developing and fall off.
Temperature fluctuations
Sudden changes in temperature are one of the most common reasons for fruit drop in trees and vegetables. Spring return frosts or sudden nighttime cold after a hot day cause severe stress in plants. In cold weather (below 12°C), roots poorly absorb nutrients, disrupting the normal development of fruit sets and causing them to fall off. Heat-loving crops suffer the most in such conditions: tomatoes, peppers, and cucumbers.
Problems can also arise in a tree that was damaged by frost in winter. A difficult winter is indicated by cracks in the bark (frost splits). Even if such a tree blooms in spring, due to a lack of strength after a harsh winter, it will shed most of its fruit sets.
However, not only cold can be the cause of the problem. Fruit loss in vegetable crops can also occur in extreme heat. At temperatures above 30–35°C, pollen becomes sterile, preventing pollination. As a result, unpollinated flowers begin to wilt and fall off.
Nutrient deficiency
Another important factor is the lack of nutrients. This equally applies to both garden and orchard crops. If the soil is poor in nitrogen, phosphorus, potassium, calcium, or micronutrients, the plant does not receive the necessary “building blocks” for fruit formation and sheds excess fruit sets it cannot “feed.” Often this happens due to incorrect or irregular fertilization. For example, gooseberries may drop immature fruits due to potassium deficiency, strawberries due to lack of phosphorus and potassium, cucumbers due to boron. Many fruit trees respond to calcium deficiency this way.
Insufficient pollination
Pollination problems also play a significant role. In plants that require cross-pollination (cucurbits, apple trees, cherries, etc.), the absence of pollinating insects becomes a serious obstacle to fruit set formation. If there are few bees or other pollinators, or if the weather is rainy, the pollination process is disrupted. As a result, unpollinated flowers dry up and fall off.
Excess or lack of moisture
Another reason for fruit loss may be improper watering. Both excess and lack of moisture negatively affect the plant. For example, overwatering leads to root rot and nutrient uptake disruption. When the soil dries out, roots cannot extract and deliver water to the fruits. In both cases, the plant responds by shedding fruit sets to conserve energy for survival.
It is very important that the water for irrigation is warm—this temperature is most comfortable for plants. If you water the garden with cold water, the plants will become stressed and shed their fruit sets even faster.
Overcrowded plantings
When plants are planted too closely, they lack light and air. This provokes disease development, impairs pollination, and leads to competition for resources, causing weak fruits to die off.
The same happens with overcrowded canopies on fruit trees. In this case, in addition to the reasons mentioned above, fruit drop can also result from the tree expending too much energy to nourish numerous shoots. There are no resources left for fruit development, so it sheds the “unnecessary” load.
Diseases and pests
Another reason for harvest loss is various infections or pest attacks.
Late blight, powdery mildew, or alternaria affect leaves, stems, and fruit clusters, depriving the plant of the ability to feed and develop properly. Viral diseases (such as mosaic or leaf curl) cause fruit deformities and render them non-viable. Some bacterial infections, like rot, can also lead to fruit drop.
Pests can be just as harmful. Aphids, spider mites, whiteflies, or thrips feed on plant sap, weakening the plant and disrupting nutrition. Some pests, such as blossom beetles, directly damage flowers and fruit sets, leading to their loss. Additionally, insects often carry viral diseases that further deteriorate the plant’s condition.
How to prevent fruit drop
The most important step is to create optimal conditions for plant growth and fruit formation. It is necessary to carefully monitor air temperature and humidity, especially during flowering and fruit set. If we are talking about a greenhouse, it should be ventilated regularly to avoid overheating, and in open ground, plants should be protected from strong winds and heat using covering material.
Fertilization plays a key role in preserving fruit sets. Plants require balanced nutrition, so it is important to apply complex fertilizers in a timely manner. At the stage of fruit formation, special attention should be paid to potassium and phosphorus fertilizers (ash, superphosphate, potassium sulfate): they stimulate fruit growth and strengthen the plant.
Before flowering, apply a nutrient solution made from 2 tablespoons of potassium sulfate and the same amount of urea dissolved in 10 liters of water. Application rate – three buckets per tree. Then, during fruit ripening, carry out the next feeding. This time use 3 tablespoons of nitrophoska dissolved in 10 liters of water. Application rate – two buckets per tree.
Also, during flowering, it is useful to apply micronutrients, especially boron, which promotes an increase in flowers and fruit set. For more effective flowering, trees during this period should be foliar-fed with fertilizers containing boron. For this, you can use boric acid (2 g of powder dissolved in a small amount of warm water, then bring the volume up to 10 liters) or a ready-made complex fertilizer with boron (for example, KompleMet Bor). For treating vegetable crops, a useful solution is prepared from 1 liter of water and 0.5 g of boric acid.
Fruit trees suffering from calcium deficiency can be saved from crop loss with calcium nitrate (1 tablespoon per 10 liters of water, consumption – up to 30–40 liters of solution per adult tree). However, nitrogen fertilizers should be limited during this period, as they stimulate foliage growth at the expense of fruiting.
Watering is also very important for proper crop ripening. It should be regular and moderate. Soil moisture must be monitored throughout the growing season, especially during fruit formation. Watering is best done in the morning or evening to avoid moisture evaporation in hot weather. Mulching will help retain moisture and protect roots from overheating.
It is also necessary to monitor the temperature. To minimize the negative impact of temperature fluctuations, it is important to take care of plant protection in advance. In open ground, covering materials can be used to protect against cold. Drape the protective material over hoops or directly on the plants: it will help smooth out temperature swings.
In greenhouses, plants more often suffer from heat than from cold. To avoid overheating, it is advisable to install thermostats in the greenhouse and ventilate the space regularly. Timely watering and soil mulching will also help create more comfortable conditions for plants.
Sometimes plants shed fruit sets because there are too many of them. This often happens with apple and pear trees, which tend to produce an excessive number of flowers. In such a situation, it is recommended to thin the fruit sets. To do this, on the 3rd–4th day after flowering begins, walk through the garden and manually remove excess inflorescences, especially on young or weakened plants – this will allow the remaining fruits to develop fully.
Eliminating overcrowded plantings – another cause of fruit drop – can be achieved through proper plant shaping. Pinching tomatoes and cucumbers improves ventilation and light access to the plant. Trees also need timely pruning. Regularly thin the crown and remove branches growing inward, as well as crossing, shading, or weak shoots, etc.
To avoid pollination problems, try to attract pollinating insects to your garden. This can be done by planting nectar-rich plants near the main crops (calendula, matthiola, lavender, mint, lemon balm, basil, sage, rosehip, etc.).
Another method is to treat plants during flowering with a honey or sugar solution. To prepare it, dissolve 1 tablespoon of honey or sugar in 1 liter of water. Spray the blooming trees and plants with the sweet solution early in the morning in dry, windless weather. After treatment, insects will catch the scent and are sure to visit the area.
If pollinators are still lacking, artificial pollination can be used by manually transferring pollen from one flower to another with a brush.
To protect plants from diseases, it is important to carry out preventive treatments regularly. The use of biological products or fungicides at early growth stages helps prevent infection. It is also important to follow crop rotation, promptly remove diseased plant parts, and avoid overwatering the soil, which promotes fungal development. Clean tools and disinfecting greenhouses also reduce the risk of disease.
To protect the crop from pests, regularly inspect plants, especially during flowering and fruit formation. At the first signs of infestation, biological control agents or folk remedies (infusions of garlic, tansy, wormwood, marigolds, etc.) can be used. Attracting natural enemies of harmful insects, such as ladybugs, will also help. If the number of pests is already high, chemical insecticides can help control them.
Fruit drop is a signal that the plant is experiencing stress or a lack of certain resources. To preserve the harvest, it is necessary to provide favorable conditions for plant growth, paying special attention to nutrition, watering, pollination, and protection from diseases and pests. Only a comprehensive approach will help minimize losses and ensure a bountiful harvest.
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