Why cucumbers have so many barren flowers: reasons and what to do

Cucumbers can bloom profusely but fail to produce fruit. The main reasons for the prevalence of barren flowers on the bushes are related to poor agricultural practices. Fruit ovaries form only on female flowers. Experienced gardeners know what to do when cucumbers produce numerous male buds. Proper plant care and folk remedies, discussed in the video, can help reduce their number.

What does a barren flower look like on a cucumber?

Cucumber is an annual plant that can produce flowers of different sexes. Asexual flowers are buds that do not form ovaries. These include:

• male flowers with stamens, which are necessary for pollination;
• female pistil buds that have not been exposed to pollen.

Empty flowers form on cucumbers with dioecious flowers. They are easy to distinguish: female buds are borne on elongated thickenings, while male buds are borne on thin stalks. Cross-pollinated varieties are intended only for open ground. Self-fertile and parthenocarpic cucumber varieties are more suitable for greenhouse cultivation. They do not produce empty flowers. Buds of the first group are self-pollinating, containing both stamens and pistils. Parthenocarpic hybrids produce fruit without pollination.

Early cucumber varieties have roughly equal numbers of male and female flowers, so there are few empty flowers. Buds open almost simultaneously on their vines. Mid- and late-season new hybrids have the same characteristic. The more female flowers a plant has, the higher the yield. Pollination occurs by insects or wind. The pollen comes from the male flowers, which are more abundant at the base of the stem and at the crown. After pollination, the empty flowers dry up and fall off.

Causes of barren flowers and methods of control

Improper care of cucumbers can lead to the development of numerous barren flowers. To avoid a fruitless harvest, it's important to identify the cause and correct the situation. Numerous factors contribute to the appearance of barren flowers, including poor-quality seeds, planting and care errors, and unfavorable conditions. Agronomic practices and folk remedies can help reduce the number of barren flowers on cucumbers.

Poor quality seed material

To avoid unpleasant surprises, it's best to buy cucumber seeds from reputable agricultural companies. Not all varieties are suitable for home-grown seeding. Bushes grown from hybrid seeds often produce large numbers of barren flowers. Furthermore, seed should not be collected from crooked or diseased cucumbers. Seeds should be collected from female cucumbers. These are identified by the number of seed chambers and facets. Male cucumbers have three, while female cucumbers have four.

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Planting young seeds can cause cucumbers to have barren flowers. Last year's planting material produces bushes that produce predominantly male flowers. This situation cannot be corrected. It's best to plant seeds collected 3-4 years ago. If such material is unavailable, you can "age" fresh seeds by hanging them in a cloth bag over a radiator. Heat the seeds at 28-30°C for a month.

Incorrect watering

Cucumbers require moderate watering. Both excess and insufficient moisture can lead to an abundance of male flowers, especially in a greenhouse. Overwatering promotes healthy stems and leaves, and produces numerous male flowers. Drought can cause plant death. During the active growth period, moisten the soil around the plants daily. The water temperature for irrigation should not fall below 20°C. It is recommended to let it settle before use. Pour water into grooves or under the roots, avoiding contact with foliage.

During cooler periods, watering is reduced. During rainy weather, outdoor plants receive sufficient moisture from precipitation. One trick will stimulate the formation of female buds on cucumbers: stop watering when the bushes bloom. In extreme conditions, plants produce primarily female flowers to produce more offspring. Watering is resumed when the fruit sets.

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Heat and cold

Cucumbers are heat-loving plants. The optimal temperature for good development and fruiting is 22 to 25°C. However, prolonged heat, especially under plastic or polycarbonate covers, is another cause of numerous barren flowers. At temperatures as low as 27 to 28°C, pollen becomes unsuitable for fertilization. Ventilating the greenhouse, watering generously, and mulching the beds will help. A layer of dry grass or compost retains moisture and inhibits weed growth.

If the summer is cold, cucumbers will produce few female buds. If there's insufficient warmth, few cucumbers will form. If the air temperature drops below 15°C, watering should be suspended until warmer weather returns. To avoid missing out on a harvest, select cucumber varieties suitable for outdoor cultivation. The greenhouse should be equipped with supplemental heating in case of sudden cold snaps.

Crowding density and lack of light

Insufficient light is often the cause of numerous barren flowers on cucumbers. If cucumbers were sown in a shaded area, shortening the main shoot and reducing watering can help. For early-ripening plants, pinch the stem after 9-10 leaves, and for mid- and late-ripening plants, after 7-8. This will stimulate the growth of lateral shoots, which produce female flowers.

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When planted too densely, the plants suffer from a lack of moisture and nutrients, and they shade each other. In such dense thickets, bees cannot reach the flowers to pollinate them. Crowding cucumbers too closely together in a garden bed negatively impacts their development: stems grow slowly, and only barren flowers form. The recommended planting pattern for cucumbers is 25x25 cm. Dense plantings should be thinned by pinching the main shoot at the base.

Often, cucumbers develop numerous barren flowers in greenhouses, and what to do about them is the main problem. Therefore, in greenhouses, particularly on windowsills, it's essential to plant parthenocarpic varieties. Artificial pollination can help eliminate barren flowers in the absence of bees. This procedure is performed in the morning, following these recommendations:

1. Stamens from different male corollas are applied one after another to the stigma of female flowers.
2. Pollen can be easily transferred with a brush with soft bristles.
3. Pollination should be carried out in the first hours of bud opening, when the pollen is most viable.
4. The optimal air temperature for pollination is +25°C.

Incorrect feeding

If there's too much nitrogen, cucumbers will become overweight, i.e., develop foliage. The plants will bloom, but the cucumbers won't form. To restore the nutrient balance, fertilize the soil with organic matter and mineral fertilizers before sowing the seeds. For every square meter, you'll need 10 grams of potassium chloride, 20 grams each of potassium sulfate, urea, and superphosphate. If fertilizer isn't applied during the fall tillage, you'll need to feed the plants with a nitrogen fertilizer two weeks after germination.

For a good harvest, it's important to maintain a proper fertilizing regimen. Cucumbers respond well to potassium-phosphorus mixtures. At the two-true-leaf stage, plants are fed with nitrophoska, dissolving 10 g of the substance in a bucket of water. The beds can be watered with cow manure diluted 1:10. Bird droppings are dissolved in water at a ratio of 1:20. Use 0.5 liters of fertilizer per plant.

It's important to alternate organic and mineral fertilizers. For watering cucumber beds, use commercial fertilizers such as Kemira Universal, Agricola, and Ideal. Once the plants bloom, stop using nitrogen-containing fertilizers. During the fruiting period, water the plants with an ash infusion or a superphosphate solution. Fertilize the cucumbers four times per season.

Diseases and pests

The number of female flowers decreases when cucumbers are affected by powdery mildew. This condition is caused by frequent watering, dense plantings, and excess nitrogen in the soil. If left untreated, the plants will die. As a preventative measure, it is recommended to treat the bushes with a colloidal sulfur solution once a month. The solution is prepared at a ratio of 4 g of powder per 1 liter of water. For 10 m² plantings will need 1 liter of working solution.

Barren flowers are formed when bushes are attacked by insect pests. Signs of their presence include yellow spots, webbing, and dark spots on leaves and shoots. Plants stunt, and leaves dry out. This pest is especially dangerous for cucumbers. spider miteIf pests are detected on plants, insecticides or acaricides are used. Folk remedies can also help: spraying the tops with garlic or hot pepper infusion, or sprinkling damp leaves with tobacco dust. Plants are treated once a week for a month, then take a 20-day break.

Garden ants cause significant damage to cucumber beds. They carry away pollen, which slows the fertilization of female flowers. Cucumbers produce few ovaries, reducing yield. Before sowing seeds, it is recommended to pour boiling water over the soil. Ants in a greenhouse can be controlled by creating a water barrier, such as a stream. This will prevent the insects from entering the greenhouse and harming the plants. If ants do appear in the beds, they can be controlled with Bazudin or Muravyed.

Preparations for ovary stimulation

To improve fruiting, you don't need to resort to the recommended folk remedies. Safe products available on the market can regulate the ratio of female to male flowers:

1. Borogum is a complex fertilizer for vegetable crops. The main nutrient is boron, which stimulates the formation of female flowers. A solution is prepared from 1 teaspoon of fertilizer and 0.3 liters of water. Cucumbers are sprayed during flowering.
2. Ovary is a biological growth stimulant. The product replenishes nutrient deficiencies and promotes fruit formation. To feed cucumbers, dissolve 2 g of powder in 1.4 liters of water. The application rate is low—300 ml per 5 m.²Plants are sprayed twice: before flowering and at its peak.
3. Bud is a complex of micro- and macroelements necessary for the complete nutrition of cucumber plants. The product stimulates the formation of cucumbers, increasing yields. To prepare a working solution, you will need 10 g of powder per bucket of water. Cucumbers are sprayed during the budding phase and during fruit set. For 5 m² 2 liters of solution are used for plantings.

Prevention of barren flowers

To avoid the formation of a large number of barren flowers on cucumbers, the following measures are taken:

1. Plants are protected from harmful insects using chemical and biological preparations.
2. Before sowing, the seeds are treated with a weak solution of potassium permanganate and dried.
3. Only self-pollinating varieties are grown in a greenhouse or hotbed.
4. Plants are planted at a distance of at least 40 cm.
5. The beds are located on the south-eastern side of the plot so that they are well lit by the sun.
6. When fertilizing cucumbers, organic fertilizers are alternated with mineral ones.
7. We combat barren flowers by pinching back long shoots to prevent them from crowding the plantings. Don't pluck off shoots; it's best to trim them with scissors.
8. In rainy weather, insects do not fly, so it is necessary to pollinate the flowers artificially.

Cucumbers must be picked carefully to avoid damaging the shoots, otherwise the plant may die. The cucumbers are easily cut with a knife. Harvest frequently—every two days. Avoid overgrown cucumbers, as they deplete the plant. The plants will not have the energy to form new fruit, as all the nutrients are spent on growing the cucumbers.

Farmers' Advice

Experienced gardeners know what to do if cucumbers have a lot of barren flowers. They recommend following these rules:

1. The beds should be watered early in the morning or after 6:00 pm, when it is no longer hot.
2. You cannot loosen the soil at the base of the bush, otherwise you may damage the roots.
3. It is advisable to spray bee-pollinated cucumber varieties with a sweet solution prepared from 300 ml of warm water and 1 tbsp. of sugar or honey.
4. To reduce the number of barren flowers on cucumbers in a greenhouse, open windows and doors regularly. High humidity can cause pollen to become heavy and prevent it from dispersing.
5. It is necessary to regularly get rid of weeds that shade the plantings and absorb nutrients from the soil.
6. After watering, the soil around the bushes should dry out.
7. To attract bees, it is recommended to plant several honey plants between the rows: thyme, lemon balm or echinacea.
8. If the shoots are tied to a trellis, air circulation and illumination of the plants will improve.

When considering what to do when cucumbers are blooming with only a single, empty flower, it's important to first determine the cause. Removing male flowers will only hinder fruiting. To solve the problem, correct any shortcomings in plant care. Adhere to a fertilizing regimen and avoid over-fertilizing the plants. Disease prevention and timely harvesting are essential. To ensure a consistent harvest, care must be taken at every stage of cultivation.