Green beans are one of the most widely grown plants in the world; they are a dependable and simple-to-grow crop. They announce the arrival of summer for their sustenance as they prefer full sun, well-drained soil, and warm temperatures.
Beans are one of the first vegetables harvested because they can produce pods all summer. Beans are mostly green, but they also come in red, yellow, purple, and streaked varieties. Green beans can be circular or flat, with a length of a few inches.
All parts of the plant, from roots to leaves, must be healthy so you can maximize pod production. However, green beans can often develop yellow leaves if not properly cared for, in extreme cases chances are their plant may die.
Keep reading the article further to know more about the reasons behind green bean leaves turning yellow in detail.
Causes behind green bean plant leaves turning yellow
1. Imbalanced soil
Cause- The first step is to inspect the planting location, as your soil could be the culprit. Check to see if the soil is well-drained and in full sun and if it has been amended with a lot of good compost. pH imbalances in your soil could lead to a condition called iron deficiency chlorosis – where the plant can’t properly absorb iron.
Green beans grow well in sandy or silty loam soils. They can, however, thrive in a wide range of soil types, with the exception of clay-rich soils. They prefer soil that is neither acidic nor alkaline, with a pH between 5.5 and 7.0.
Fix- You can test the soil with a soil test or by pouring vinegar into it. The soil is alkaline if it bubbles from the vinegar. If your pH is higher than 7.0, use a soil acidifier (like this one) to reduce alkalinity. You can later use your soil acidifier on your blueberry bushes too.
Organic mulch can feed the soil and prevent it from becoming overly dry. To help clayey soil drain, you can add sand – even builders sand if you have it on hand. To improve water retention, amend sandy soil with organic matter like manure or compost to the soil.
Adding chelated iron is something you can try for iron deficiency chlorosis. Chelated iron also helps lower soil pH.
2. Insufficient Water
Cause- Water is the vehicle that transports nutrients to the most remote parts of your plant’s body. Your green bean plants may become discolored as a result of poor watering practices such as under or over-watering.
Yellow spots appear, and the entire leaf eventually turns yellow. Overwatering is harmful because it suffocates the plant, deprives it of vital nutrients, and can even lead to root rot. This is true for seedlings, too. Check this article on why seedlings become yellow.
The lack of vital nutrients in plants can be overcome by using rice water as a substitute for watering plants. Excessive soil moisture can cause root rot, which causes yellow leaves in beans. Whereas, insufficient watering will cause the plant to wither and die prematurely.
Fix- A green bean plant requires about two inches of water per week, which means it must be watered on a daily basis in the heat of summer.
You can probe the soil around 2-3 inches deep with your fingers or a stick to see if your green bean plants require watering. If dirt sticks to the stick or your finger, don’t water. If the soil seems dry, water your plants.
3. Pest damage
Cause- Green bean plants are especially vulnerable to pest damage and they seem to be a magnet for pests. Aphids, for example, can cause your plant’s leaves to wrinkle and turn a yellowish color. Sap-sucking insects such as the potato leafhopper, thrips, and two-spotted spider mites can cause yellowing and deformation of the plant.
Fix- Ladybugs and other beneficial insects, such as wasps, can help keep pests at bay in your garden. These insects will consume pests in your garden and prevent pest growth.
4. Lack of nutrients
Cause- Insufficient fertilization may have an effect on the health of your Bean plant, resulting in yellow leaves. A shortage of nitrogen can cause plants and leaves to turn light green or yellow – sawdust, for example, eats up nitrogen in your soil, so be sure not to use it as a mulch or soil amendment. Insufficient harvesting can also be to blame. Manganese deficiency causes the yellowing of older leaves and the formation of brown patches.
Fix- A nutrient testing kit can determine the specific nutrient which is deficient in the soil. After receiving the results, you can fix the problem by purchasing soil-specific fertilizer.
Following nutrient correction in the soil, the green bean plant should begin to regain its green hue. But if in doubt, in the absence of a soil test, you can add a 5-10-15 fertilizer, and add it regularly throughout the cropping season.
5. Fluctuation in temperature
Cause- Green beans are one of those plants that absolutely adore strong light and they should be placed in full sun. They can withstand hot weather, but won’t tolerate any type of cold. So your climate dictates how long your green bean season will be.
Fix- Green bean plants thrive in temperatures ranging from 65°F (18°C) to 85°F (29°C), and they grow optimally at these temperatures. There is also a temperature requirement for the soil, which is 55°F (12°C). Most importantly, they enjoy direct sunlight, so don’t plant them in shade. Unfortunately, there’s not much you can do about the weather, but you can try growing green beans in a greenhouse to extend your season.
6. Infection or disease
Cause– A viral infection can also cause yellow leaves on garden beans. The mosaic virus can infect a wide range of vegetables, and there are several bean mosaic viruses that appear in various parts of the country.
The first symptoms of the mosaic virus in green beans are multicolored spots on the leaves, which eventually fade to a completely yellow to brown leaf. A virus could be the cause of yellow leaves on bush or pole beans as well. Virus problems can arise from low nutrient levels or herbicide damage, but they are most likely caused by infected bean seeds.
Water can spread bacterial diseases like blight, especially if you have blight in other parts of the garden.
Fix- To avoid the spread of pests and diseases, avoid watering the foliage of your green bean plants. Remove affected parts of the plant. Wash your pruners after cutting infected plant debris in a bleach and water solution to prevent disease spread between cuts.
After removing the affected plant tissue, spray the entire plant with fungicide or neem oil. Neem oil works great for blight prevention and treatment throughout the entire garden.
7. Plant competition
Cause- Green bean plants will not receive adequate sunlight, nutrients, or air circulation unless they are thinned out at the proper time. Overseeding beans is frequently the cause of overcrowding.
Sowing beans too close together will cause them to compete for nutrients, which, in combination with other environmental factors, can lead to yellow leaves.
Fix- Allow enough space for your plants to grow and expand as they mature. Sow green beans in rows that are at least 16 inches apart, and space them at least 3-4 inches apart within the row. Enabling the air to circulate freely will help prevent the spread of disease and pests.
Green beans frequently have yellow leaves that may have you worried. It reflects the poor health of the plant and the fact that your harvest might be impacted too. Pinpointing the exact cause of yellowing leaves is difficult, but some culprits, like aphids and drought are obvious. It’s better to take action sooner, rather than later, and save your beans so that they can crop until the frost comes.