It is no secret that cucumber is the most popular vegetable grown in the gardens of our compatriots. As such, it makes unpretentious care and high yields. However, it often happens that the leaves of the plant turn yellow and become covered with spots.
What is this phenomenon: a disease or violation of the rules of care, is it necessary to treat it and with what? Let's try to figure it out.
Yellowing cucumber seedling leaves
Independent cultivation of cucumbers is not very troublesome, but requires certain skills and knowledge. Often, beginning gardeners are faced with the problem of yellowing of just the first leaves that appear.
You should not panic - often such problems are not the result of plant disease and are solved quite simply if you notice the first signs in time.
Learn about new non-standard methods of growing cucumbers: in bags, casks, plastic bottles, buckets, using the hydroponics method.
Why it happens
So, why does it happen that cucumber seedlings at some point begin to dry the edges of the leaves? Most often, this phenomenon makes itself felt when the second leaf appears on the shoot, the first in this case begins to dry and become covered with yellowness, there may be several reasons for this:
- Infringement of the mode of watering, an overabundance, but more often a lack of moisture.
Did you know? It turns out that thorny tubercles on young fruits act as a kind of sweat glands for vegetables and are designed to remove excess moisture.
- Insufficient seedling coverage.
- A sharp temperature drop - it is impossible to allow the soil to cool to a temperature below 17 ° C, because in this case the plant root system cannot obtain nutrients from the soil.
- Lack of nitrogen and potassium or imbalance in the soil.
- Close capacity for seedlings.
What to do
If you notice that the leaves of the cucumber seedlings began to turn yellow, you need to find out the reason in order to know what to do next:
- First you need to exclude the defeat of plants fungal diseases or parasites.
- Properly organize the watering of the plant, avoiding drying out of the soil and stagnant water. Cucumbers love moisture, so watering should be abundant and systematic.
- Provide a normal microclimate for seedlings, eliminate temperature drops, in case of insufficient illumination, arrange lighting.
- Apply complex fertilizers at the growth stage of the seedlings to provide the young plant with potassium and other important nutrients.
Important! Very often, in order for the seedlings to be in a comfortable temperature regime, gardeners use expanded polystyrene, which is treated with special impregnations, which release toxic substances into the atmosphere. The plant can be poisoned by these toxins, which leads to yellowing of the foliage.
Yellow leaves of cucumbers on the windowsill (balcony)
Cultivation of cucumbers on the balcony or windowsill in an apartment is practiced by amateurs to eat fresh vegetables even not in season or by those who do not have a summer cottage. Very often in such cases there is a problem with the leaves of the plant, they begin to turn yellow and dry, the reasons why this happens a little.
Why it happens
- Wrong watering mode - in room conditions cucumbers require more sparse watering, therefore, with an excess of water may begin to turn yellow foliage.
- Insufficient humidity in the room or on the balcony.
- Nutrient deficiencies in soil.
- Poorly selected soil, the presence of disease or parasites.
What to do
The solution to the problem is to eliminate errors in the care.
- It is important to observe the mode of watering. Home-grown cucumbers are watered as moisture-loving houseplants: once a week, but abundantly, making sure that there is no stagnation of water. Otherwise, root decay will begin, and the leaves will continue to turn yellow and dry.
- Establishing an adequate humidity regime in the room. To do this, you need to regularly spray the leaves of the plant, and it will also be nice to build a kind of greenhouse, pulling the film on the window.
- It is necessary to regularly feed the culture with mineral fertilizers.
- Buy high-quality ready-made soil, or, if the soil is taken from the garden, shed it with a solution of potassium permanganate.
Yellowing cucumber leaves in a greenhouse
Many gardeners are engaged in growing cucumbers in greenhouses, and many of them have probably come across the fact that the foliage suddenly turns yellow. However, not everyone knows what this phenomenon is connected with and what needs to be done to prevent it in the greenhouse. 
Did you know? It turns out that the first greenhouse cucumbers appeared in Ancient Rome because the Roman ruler Tiberius expressed a desire to see a fresh, crispy vegetable on his table every day.
Why it happens
The reasons for the yellowness and drying of the leaves of cucumbers in the greenhouse are similar to the previous cases, although they have their own specifics:
- The first and main reason is often banal cold. Often, after planting a vegetable in a greenhouse, frosts occur, and, as we already know, a sharp drop in temperature not only affects the leaves, but also inhibits the growth of the plant as a whole and lowers its resistance to viruses and parasites.
- Another likely cause may be climate inconsistency with agrotechnical requirements. For example, insufficiently intensive watering in the complex with high air temperature in the greenhouse - cucumbers do not tolerate heat and low humidity and slow down their growth and development.
- The lack of trace elements in the soil.
The damage of the leaf plate of cucumbers can be caused by plant pests: aphids, midges, spider mites.
What to do
- It is necessary to provide additional warming of the greenhouse in case of frost return.
- Maintain an adequate indoor climate: moderate temperatures at all times, high humidity, airing.
- Periodically to feed the plants with microelements, you can use any universal mineral fertilizer of industrial production.
- It is important to remember that the cause of the deterioration of the foliage of a plant may be associated with the manifestation of diseases characteristic of this culture: powdery mildew, root rot, bacteriosis, and a number of other diseases of a fungal nature. To combat these ailments, industrial fungicidal agents are used in parallel with the normalization of moisture and the removal of affected plants.
Yellow leaves of cucumbers in open ground
Vegetable cucumbers are the most persistent, but also more exposed to external factors., therefore, the appearance of yellowness on the leaves for them is quite common. 
Why it happens
- The reason for the yellowing of the leaves is often a lack of light if cucumbers grow on a darkened part of the vegetable garden. Also often violent growth of the crown contributes to the fact that the leaves that are at the bottom, get a minimum of light and turn yellow. Such a situation in the garden is a normal phenomenon and does not require special measures.
- Lack of nutrients in the soil.
- Violation of the irrigation regime is equally dangerous as a shortage of water and its excess.
- Overcooling of the root system. Such a phenomenon often affects plants planted in open ground. Night frosts can not only reduce the harvest, but also completely destroy the root of the crop.
- Cucumbers are hot. You can often notice that yellow spots appear on the leaves of the cucumbers. Why this happens - the answer is simple: if after watering or rain the plant is under the rays of the scorching sun, then the leaves get a real burn.
- Natural leaf aging. This happens when the bush has already brought a significant amount of fruit and the natural process of wilting has begun.
What to do
- Clearly follow the agrotechnology of cultivation, follow the rules of watering the plant, avoid watering in the heat.
- Prevent overcooling of the plant, plant in accordance with the sowing calendar and focus on the weather forecast.
Important! Watering cucumbers should be carried out with slightly warm water heated in the sun, because cold water will cause hypothermia and death of the plant.
- Regularly fertilize cucumbers with mineral fertilizers, mulch the soil to better retain moisture and heat.
So, having familiarized with the problem of yellowing of leaves on cucumber bushes, one can draw conclusions: before taking steps to eliminate the phenomenon, it is necessary to find out the reasons for eliminating diseases. In most cases, the leaves turn yellow as a result of violations of agricultural technology, and there is no need to specially treat the plant.
