Cucumber is a traditional American vegetable. They are grown on every plot of land because of the high demand for their fruit. They are salted, acidified, pickled, frozen, and, of course, what American doesn't like to crunch on them! At first glance, this may seem like an undemanding crop. However, it is very fragile and sensitive. If planting and care are not properly organized, the plant will immediately "express dissatisfaction" - the leaves begin to turn yellow and dry out from the edges. This Bubgo article explains the reasons why cucumber leaves turn yellow and how to help them.
It is not uncommon for all the lamellae to later change color and wilt and fall off. The plant suspends further development and refuses to flower and bear fruit. Why does this happen? What is wrong with it? Let's wait and see. The causes of unhealthy cucumbers can be divided into natural (climatic) and agronomic.
The first group can include.
1. Insufficient light. If the plants are planted too densely, the lower lamellae will yellow due to lack of light.
2. Lack of heat. Those below are affected first when there is a prolonged cold spell. In greenhouses where temperature values can be controlled, it is recommended to keep these values at 77-86 °F (25-30°C) during the day and 64-68 °F (18-20°C) at night.
3. Excessive sunlight. If the cucumber bed is located in an elevated area with frequent sun exposure, then the cucumber slab will begin to turn yellow and subsequently dry out under the scorching sun.
4. The soil is not moist enough. If the edges of the cucumber leaves turn yellow in the greenhouse, this can also be attributed to agronomic reasons. However, outdoors, it is a climatic cause. The roots of cucumbers are in the topsoil, which tends to dry out quickly if it is not watered enough or if there is little rainfall. If there is a lack of moisture in the air or soil, the plant suffers and responds to drought by yellowing and drying out. This pathological process begins at the edges. If the situation worsens, the plant will wilt completely. Lack of moisture in hot, dry weather is one of the most common causes of leaf scorch, not only in outdoor beds but also in greenhouses.
5. The presence of pests. Aphids of melons. Greenhouse whiteflies and other guys that eat green cucumbers cause a lot of damage to cucumbers. These pests settle on the bottom of the plate and suck the juice from it. As a result, the edges of the cucumber leaves turn yellow and dry out, and may even fall off.
6. Development of diseases. These diseases include hypersporidiosis, bacterial diseases, fusarium, and powdery mildew. Various fungal and bacterial diseases infect plants, causing the edges of the leaves to turn yellow first and then the entire leaf. Fungal infections most often occur during sudden changes in temperature, such as when heat waves are replaced by cold, cloudy days and heavy rains. The presence of brown spots on the leaves and yellowing of the edges can indicate the presence of an infection. Fusarium can cause up to 90% of plants to die.
7. Inadequate pollination. Applies to hybrid cucumbers that produce mainly female flowers. Without the help of pollen from male flowers, no fruit will be produced. Sometimes the plant may start to wilt, mainly the plates start at the edges.
8. Natural aging of the plant. This process occurs at the end of the growing season. The stems can no longer produce cucumbers and the canopy gradually withers, starting from the edges. This indicates that it is time to empty the beds.
Tip: If you have made this "diagnosis", it is almost impossible to fight it. Tear out the diseased plant and remove it from the bed.
Cucumber cultivation is considered to be agronomically unsuitable in terms of
1. Deficiency or excess of nutrients.
2. Incorrect watering.
3. Should not be too frequent or infrequent. Too much water replaces the air in the soil and impairs the normal oxidation of organic compounds. The supply of nutrients to the roots and the entire plant is slowed down. Prolonged overwatering can lead to root rot.
Inappropriate substrates. Poor, sandy soil can lead to stunting and yellowing of the leaves and subsequent drying out. This process usually begins at the edges.
Let's look at a few causes of this problem and suggest solutions.
With the invasion of pests, the medicine "insecticide for aphids, thrips, ticks" or its analogs, as well as proven folk remedies will help.
1. Dilute ammonia in water (10%) to get rid of pests.
2. Mix 2 tablespoons of ash in a bucket of water, then add half a bar of grated soap. Strain the solution and apply a foliar treatment on the leaves.
3. 200 g of brandy leaves (preferably dried) are poured into 2.6 gals (10 liters) of hot water. After two days of soaking, spray the stems and leaves.
To control whiteflies, keep the greenhouse clean, remove weeds (the main breeding place of the pest), and hang sticky traps. To prevent whiteflies from appearing, carefully cover all paths of entry (windows, doors, vents) with gauze.
Treat with Trichodermin, Quadris (before fruit ripening), and other fungicides. Be sure to follow the instructions according to the developmental stage of the plant. If the initial symptoms of cucumber "disease" appear, you can also use the following recipe.
1. Dilute ammonia alcohol (10%) in water to repel pests.
2. Mix 2 tablespoons of ash in a bucket of water, then add half a bar of grated soap. Strain the solution and apply a foliar treatment on the leaves.
3. Pour 200 grams of bok choy leaves (preferably dried) in 2.6 gals (10 liters) of hot water. After two days of soaking, the stems were sprayed.
To control whiteflies, keep the greenhouse clean by removing weeds (the main breeding ground for the pest) and hanging sticky traps. To prevent the emergence of whiteflies, carefully cover all entry paths (windows, doors, vents) with gauze.
If you can, plant another variety with male flowers nearby, which may be pollinated by insects, and this will remedy the situation.
You can infer from the pattern of yellowing what substances the plant is deficient in.
1. Lack of nutrients such as iron, calcium, manganese, magnesium, and most importantly potassium will cause the leaves to shatter and turn dark green with brown (rust-colored) borders or spots along the edges of the plates.
2. Tiny yellow-green streaks appear on the plates. It quickly becomes very yellow and the edges become dry and crumbly: these are the first signs of potassium deficiency in the ward. Some plants may also show dryness and curling of the edges of the plates. Symptoms of potassium deficiency are very similar to those of various diseases and lack of moisture in the soil. or a 1% solution of potassium permanganate.
3. If calcium is deficient, the edges will turn yellow and gradually turn brown. If you do not give any calcium supplement, the leaves will soon start to wilt and curl upwards. Adding chalk, ground eggshells, dolomite powder, or calcium carbonate to the soil is helpful.
Yellow discoloration of the leaf margins may be the result of boron deficiency. Boron supplements can be used as directed: boric acid, Biochelat-Bor.
4. Nitrogen deficiency will be indicated by a white edge. A little later, the plates will become completely discolored and fall off. Ammonium nitrate or urea can help.
As a side note.
Tip: Apply a nitrogen supplement before the male and female flowers are formed. To get a good crop, establish a nutrient regime for the plants.
Eliminating nutrient deficiencies requires regular spraying of the leaves with a vitamin mixture, potassium nitrate, and with Bordeaux mixture.
To stimulate the re-growth of the plants after being attacked by fungal and bacterial diseases (pearl fungus, bacterial diseases), I recommend the use of a foliar spray solution. Dissolve 30 grams of urea in a bucket of water and add micronutrients (2 grams each of copper sulfate, manganese, and boric acid). Apply to start around the second half of July after the first signs of disease. The treatment was repeated 2-3 more times in August, increasing the dose of urea to 50 grams to ensure complete recovery of the green mass.
This fertilizer has been tested in various local areas for many years. It has proven effective in helping cucumber shoots damaged by infection to recover, grow new lateral branches and establish fresh leaf masses. This is especially important for local high-yielding varieties where more than 50% of the total yield is produced by lateral shoots.
Folk fertilizers for cucumber organic fertilizers and various
1. cowpeas: Fill a 0.8 gals (3 l) jar with 2.2 lbs (1 kg) and add water. Leave to soak for 3 days. Add water to 2.6 gals (10 liters), stir, and filter before use. It is a good source of nitrogen and preventive medicine against powdery mildew.
2. Ash solution: Dissolve 300 grams in 2.6 gals (10 liters) of water, stir and leave to soak for a few hours.
3. Kefiran solution: dilute 0.52 gals (2 liters) of milk product in 2.6 gals (10 liters) of water. A few spoons of sugar can be added for better fruiting and to attract bees.
4. Green manure: fermented infusion of any herb.
5. Yeast feed: In a bucket of warm water, dilute a 200 g packet of raw yeast with 2/3 cup of sugar. Cover and let it ferment for 24 hours. Pour 0.26 gals (1 liter) of the filtered solution under each cucumber bush. This fertilizer improves the immunity of the plant and promotes excellent root formation.
6. Onion husk decoction: performs several functions simultaneously - as a fertilizer, immunomodulator (increases disease resistance), and biocide (treats diseases).
Tip: The formula contains a complex of essential macro and micronutrients that promote good plant growth and abundant fruit. However, it is not recommended to use it more frequently than once every 2 weeks.
Everything must be done in moderation. Overfeeding can lead to a mosaic of colors in the leaves.
As you can see, yellowing and drying of all or just the edges of the leaves are quite common. The causes are multiple. Therefore, in my opinion, it is difficult to determine if the marginal changes and drying are the end result or the beginning of a dangerous pathological process leading to greater consequences. Therefore, any change in leaf color or condition is a signal to start analyzing your cucumber plants for care or for pest and disease diagnosis.
Yellowing of plants is easier to prevent than finding remedies later. This is where the prevention methods mentioned above are important.
How do you deal with yellowing cucumber leaves? Share your suggestions with other gardeners in the comments.
