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:
- Sudden temperature changes, low average daily temperatures, frosts.
- Lack of minerals in the soil.
- Violation of irrigation technology.
- The plant is overloaded with ovaries.
- Inadequate pollination.
- Damage by insects, fungal infections.
Disturbance in care
The most optimal temperature in the greenhouse should be 22-26°C. In such conditions, it is easy for the plant to obtain nutrients from the rhizomes. When the temperature drops to 14°C, the 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 coating materials, such as Spandbond, Lutrasil, Agrotex. You can put hot water bottles. To prevent further plant disease, remove bad flowers and leaves, treat the removal site with a solution of manganese, and then spray it 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 the foliage indicate a lack of magnesium, while yellow spots are a sign of potassium deficiency. First, lighter, and then yellowed and curled leaves, crooked hook-shaped fruits indicate a lack of nitrogen in the soil. Cucumber seedlings a few days before planting in greenhouses should be sprayed with a solution of microelements and fed with fertilizers.
In addition, during the vegetative development of the plant, it is necessary to constantly feed it. To do this, use 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 strictly follow the instructions when using industrial mineral fertilizers.
This vegetable loves moist air and soil. Therefore, poor watering can cause the plant to turn yellow. 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 volume of watering. Intermittent and poor-quality watering will have a bad effect on the embryos and fruits of the cucumber.
Cucumber diseases
Some diseases can cause yellowing of foliage and fruits:
- Fusarium wilt may lead to the death of the plant. The fungus produces toxins that completely block the flow of beneficial substances to the leaves, embryos, fruits and stems. The soil in the greenhouses should be immediately replaced, and the variety of vegetable should be changed in subsequent years.
- Powdery mildew - a fungus that manifests itself by the appearance of small light spots, then they slowly spread over the entire surface. A white or reddish coating forms on the surface of the leaf blade. Then the leaves and buds turn yellow and dry. To prevent the disease, it is necessary to treat the soil in the winter garden before planting with a solution of manganese or green manure.
- Root rot is formed as a result of improper moistening of the plant and non-compliance with the temperature regime. When watered with cold water, during a sharp cold snap, the rhizomes begin to crack and the leaves are left without nutrition, begin to turn yellow and wither. The diseased plant is removed along with the diseased soil. Crushed coal and ash are added to the soil and sprayed with a solution of copper sulfate.
Parasitic insects can spoil the development of plants:
- Spider mite - a pest that appears on the inside of the leaf and weaves a small web. Breeds in warm conditions. Destroyed with special chemicals.
- melon aphid threatens the fruits throughout the fruiting period. Lives on the inside of the leaf and feeds on its sap. Moves from weed. To get rid of them, they weed the beds and destroy the weeds. Spray with infusions of tobacco and capsicum, and soap solution.
- Greenhouse whitefly also a weed pest. Causes leaf wilting. It is necessary to destroy the 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 a greenhouse can lead to underdeveloped 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 ensure access of 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 grams of boric acid per 1 liter of water. Also, for the next seasons, it is worth planting the following in cucumber greenhouses: honey plants - borage, dill, etc. This is why cucumbers turn yellow.
For various reasons, cucumbers in a greenhouse turn yellow; what needs to be done is to eliminate the cause in a timely manner. You can use either traditional methods or the latest chemicals. The main thing is to properly care for and grow plants. Then you will get a rich harvest.
