It happens that a greenhouse plant, its leaves and fruits begin to turn yellow. To get a good harvest, you need to look for the root cause and eliminate it.
There may be several reasons:
- Sharp temperature changes, low average daily temperatures, frosts.
- Lack of minerals in the soil.
- Violation of irrigation technology.
- Plant congestion with ovaries.
- Inadequate pollination.
- Damage by insects, fungal infections.
Disorder of care
The most optimal temperature in the greenhouse should be 22-26 ° C. Under such conditions, it is easy for a plant to receive nutrients from the rhizomes. When the temperature drops to 14 ° C, seedlings turn yellow and stop growing, and at -1 ° C they die. To warm the plant and protect it from freezing, it is necessary to use artificial materials, films or special materials for covering, such as "Spandbond", "Lutrasil", "Agrotex". Hot water bottles can be placed. To prevent further plant disease, bad flowers, leaves are removed, the site of removal is treated with a manganese solution, and then sprayed with a solution of copper sulfate.
When the soil is poor in minerals and trace elements, the plant turns yellow, withers, and stops growing.
Light green spots on foliage indicate a lack of magnesium, while yellow spots are a sign of potassium deficiency. At first, lighter, and then yellowed and twisted leaves, crooked hook-shaped fruits indicate a lack of nitrogen in the soil. Seedlings of cucumbers a few days before planting in greenhouses should be sprayed with a solution of trace elements and fertilized with fertilizers.
In addition, during the vegetative development of the plant, it is necessary to carry out its constant feeding. To do this, use a rotted mullein or chicken droppings.
In autumn and spring, when digging the soil, you need to add rotted manure to it, this will increase the nitrogen content in it. Both a shortage and an overdose of mineral fertilizers can lead to yellowing of cucumbers in a warm garden. So you need to carefully read the annotation and follow the directions exactly when using industrial mineral fertilizers.
This vegetable is very fond of moist air and soil. Therefore, poor watering can provoke a yellowing of the plant. Greenhouse cucumbers require frequent and deep watering with warm, settled water. Cold water also causes leaves to turn yellow. Deep soil moisture is required for the full development of the root system. During fruiting, it is necessary to increase the amount of watering. Inconsistent and poor-quality watering will have a bad effect on the buds and fruits of the cucumber.
Cucumber diseases
Some diseases can cause yellowing of foliage and fruits:
- Fusarium wilting can lead to the death of the plant. The fungus produces toxins that completely block the supply of nutrients to the leaves, embryos, fruits and stems. The soil in greenhouses should be replaced immediately, and the vegetable variety should be changed in subsequent years.
- Powdery mildew - fungus, which is manifested by the appearance of small light spots, then they slowly spread over the entire surface. A white or reddish bloom forms on the surface of the leaf plate. Then the leaves and embryos turn yellow and dry... To prevent the disease, it is necessary to cultivate the land in the winter garden before planting with a manganese solution or siderates.
- Root rot formed as a result of improper plant moisture and non-observance of the temperature regime.When watering with cold water, with a sharp cold snap, the rhizomes begin to crack and the leaves remain without food, begin to turn yellow and wither. The diseased plant is removed along with the diseased soil. Crushed coal, ash are introduced into the soil, and sprayed with a solution of copper sulfate.
Insect parasites can spoil the development of plants:
- Spider mite - a pest that appears on the inside of the leaf and weaves a small web. Produces in warm conditions. Exterminated by special chemicals.
- Melon aphid threatens the fruit during the entire period of fruiting. Lives on the inside of the leaf and feeds on its juice. Goes from weeds... To get rid of weed beds and destroy weeds. Spray with infusions of tobacco and capsicum, soapy water.
- Greenhouse whitefly also a weed pest. Causes leaf wilting. It is necessary to destroy weeds, spray the plant with plain water, loosen the soil and fertilize it with peat, sawdust and humus. You can make sticky catchers to which insects will stick.
Many ovaries and lack of pollination
A large number of cucumber ovaries in the greenhouse can lead to underdevelopment of the fruits, the embryos will stop developing, turn yellow and rot. A sufficient number of ovaries on the stem is about 25-30. Excess shoots and ovaries must be removed.
Some plant varieties can only be pollinated artificially. It is necessary to provide access for insects to greenhouses. To do this, the doors must be open during the day, subject to warm weather conditions. To attract bees, you can spray flowers with special products or natural compounds, such as sweet water - 1 tablespoon of sugar or honey per 2 liters of water, or 0.5 g of boric acid per 1 liter of water. Also, for the next seasons, it is worth planting such melliferous plants - cucumber herb, dill, etc. That is why cucumbers turn yellow.
For various reasons, cucumbers turn yellow in the greenhouse, what needs to be done is to eliminate the cause in a timely manner. You can use even folk methods, even the latest chemicals. The main thing is to properly care for and grow the plants. Then you get a rich harvest.
