Help! My Green Bean Leaves Are Turning Yellow! What Now?
If your green bean plant has yellowing leaves, you are likely a little panicky trying to figure out why! There are several reasons that this may happen, from underwatering, to plant disease. In this article, amateur gardener Jason White looks at seven different causes of yellowing green bean leaves, and how to deal with it.
Green beans are a great plant to have in your garden. They’re definitely a favorite vegetable, so it’s worth growing them on your own land, whether you’re a full-fledged farmer or a fledgling gardener. However, while the growing process seems fairly straightforward, there are some issues that may show up in the form of yellowing leaves.
Some of these issues may halt the vegetable production of your plant, which can be frustrating. Yellow leaves are a symptom of a problem that needs to be corrected during the growing cycle. It’s an indication of poor health in the plant, and as such, must be addressed immediately.
There are several reasons this may be happening, so fixing your plant isn’t usually a one-size-fits-all solution. Let’s take a deeper dive into the seven most common reasons your green bean plants may have yellow leaves, including some fixes to get your plant back on track.
More often than not, the cause for green beans yellowing is improper watering. Both under-watering and over-watering your plant can cause discoloration for a few different reasons. The yellowness starts out in spots, before eventually taking over the whole leaf.
When you under-water your plant, it’s unable to absorb nutrients. Water is the vehicle that transports nutrients to the farthest reaches of your plant. Over-watering is also bad because this suffocates the plant, which also deprives it of nutrients.
It can be a bit difficult to know if you are under-watering or over-watering your plant, given that the outcome is the same. However, the solution is simple. All you have to do is take a look at the soil. Insert one of your fingers a few inches deep into the soil to determine soil moisture.
This is important to do before you try watering your plant. If the soil is obviously dry, give your plant a good drink of water. If you have planted your green beans in a container, it’s good to have a dish underneath the pot to catch excess water, so the roots can absorb it.
How to Fix:
Easy fix, just adjust the watering schedule. Sometimes, the soil may happen to be moist after testing. If so, leave the watering off for a few days. A good rule of thumb is to allow the soil to dry out a little bit before you water it next. Green beans need roughly two inches of water per week. As long as you balance your watering, you should see your plant turning green in no time at all!
Another common reason for a green bean plant to turn yellow is if it does not get the right amount of sunlight. Again, balance is key here. You’re supposed to give your plant the appropriate amount of sunlight because this is key to its photosynthesizing. Photosynthesis is the process by which plants generate their food; sunlight is essential to this.
If your plant isn’t getting enough sun, then the leaves will turn yellow from lack of nutrition. If they get too much, then the plant can end up burning, which will halt production as well. When your green bean leaves turn yellow from lack of sunlight, you may notice the lower leaves turning yellow first.
Green beans in particular are warm-season plants, and are great lovers of the sun. They will need at least 6 to 8 hours of direct sun each day. However, you will need to employ row covers to prevent over-sunning your plants. If you are able to give them the right amount of sunlight, you will notice that new growth will come in green, which is exactly what it needs to be.
How to Fix:
This is also an easier fix, compared to other potential problems. When planning out your garden, be sure that your beans will be in a spot that gets enough full sunlight, while still providing adequate protection. This will prevent any yellowing in the future. Otherwise, you may need to move your plants to a more appropriate spot to get it back to health.
In line with sunlight needs, your green beans need to be exposed to the right temperatures also. They love warmth and thrive best in temperatures between 70 and 80 degrees Fahrenheit. Anything lower than this can really cause established leaves to yellow, and will also prevent much further growth.
This is also the case for temperatures upwards of 90 degrees Fahrenheit. It’s also worth noting that low temperatures can seriously affect green bean yields, so be sure that the climate where you live is appropriate for these plants.
How to Fix:
If you live somewhere that is typically too cold to support green beans growing outdoors, and you have the resources, you can choose to plant them in a greenhouse. This way, they can be at the warm temperatures they need for most of the year.
This should prevent the leaves from yellowing, provided that a low temperature is the reason for the discoloration. Take care to provide adequate sun protection also when planting your green beans in a greenhouse, as the conditions and heat can cause burning. Otherwise, you should work to keep your plants protected from cold drafts when they are planted outdoors
Improper Soil Conditions
Yellowing can come from bad soil conditions. This is in line with their watering needs, too. Think about the soil that you use for your plant. It is imperative that it is well-draining, as this will prevent the roots from developing rot.
This also prevents moisture stress, since over-watering can really cause trouble for your green beans. The soil should be kept moist to the touch, but not overly wet.
The ideal soil for green beans is sandy and silty loam soils. However, bear in mind that green beans aren’t really picky, and can do well in most soils, except those rich in clay. Another factor to keep in mind is your green bean’s soil pH.
Green beans love neutral or near-neutral soil, tending towards alkalinity. Good pH levels are between 5.5 and 7.5. If your plant isn’t in this range, that can spell problems.
Circling back to temperatures, your green bean’s soil should be mulched. The soil temperature needs to be at least 50 degrees Fahrenheit. Adding an organic mulch can really help keep the soil warm, and can also help your soil from getting too dry.
How to Fix:
You can test the pH levels of your soil with a test kit. You can make the soil more alkaline by adding a liming agent, like agricultural limestone. Elemental sulfur, or fertilizer containing ammonium sulfate can bring the pH down. If your green bean plant is in the neutral soil it loves, then the leaves should be green again shortly.
It’s also good idea to incorporate organic matter into your green bean plant’s soil. This can be in the form of compost or fertilizer, as this can help the plant get the nutrients it may be lacking. Enriching the soil could help prevent yellowing, provided that soil conditions are the reason for discoloration.
Lack of Nutrition
One significant reason for a green bean plant’s leaves turning yellow is a lack of nutrition. As we’ve previously covered, nutrition is everything for a plant. There’s a lot that can affect the amount of nutrition your plant gets, from improper watering, sunlight, temperature, and soil conditions.
You can usually detect nutrient deficiency if the leaves are yellow, but the veins are green. The top leaves are also likely to yellow first. If this is true for your green bean plant, you should work on giving it more balanced nutrition regimen.
Green Bean plants need fertilizer to stay nourished. Using too little fertilizer can be a cause for a lack of nutrition, especially if the soil it’s planted in is poor. Plant food can make all the difference both in the health of your plant and the yield it gives you. However, when using any fertilizer, follow the instructions carefully. Too much fertilizer can cause burning in your plant, too, which is also a cause for discoloration.
How to Fix:
You can determine what nutrients your soil is lacking by purchasing a test kit. Once you have the results, you can amend the situation by purchasing fertilizer that addresses the soil’s needs. Green beans produce nitrogen, so it’s not very necessary to buy fertilizer that is nitrogen-rich. Compost can really make a difference in your green beans’ health, too. Once you correct the nutrients in the soil, you should see your plant turning green again.
If you have planted your green beans in a container, then compacted roots may be the reason for yellowing leaves. When the plant has outgrown the container it is grown in, the roots become compacted and damaged, and thus, the leaves will yellow and fall off.
This is because the roots will not be able to deliver the nutrients and water necessary to keep the plant healthy. The solution would simply be to carefully replant your green beans in a bigger container, if not straight into the soil. Pruning the roots can also help make a difference.
When planting your green beans right into the soil, aeration can really help prevent compacted roots, too. Good drainage is essential to your plant’s health, and can give the roots a good amount of space to grow.
How to Fix:
Whenever you need to replant your green beans, it’s a good idea to take a look at the color of the roots. Good roots are a pale, whitish yellow color. Darker roots could mean that rot has taken over, especially if a foul odor is present. Unfortunately, in this case, it would be best to discard the plant and start over if at all possible.
Bacterial or Viral Infection
When talking about yellowing plants, there’s always the possibility of a bacterial or viral infection being the cause for the issue. Let’s cover bacterial infections first.
You can spot bacterial infection in a green bean plant if the leaves are yellow and there are also dried up leaves and wet lesions. New leaves and pods may also be misshapen when they come in. Brown spots may develop on the leaves, ending in a yellow ring around the spot. This is usually identified as common blight. Halo blight is similar in manifestation, though there is a much more noticeable yellow halo around the spots. The lesions in halo blight usually stay quite small.
Bacterial infections, especially blight, spread through moisture. To prevent spread, you should avoid coming into contact with your plants while they are wet. Controlling weeds and pests should also help contain the disease to one plant. Destroying the affected plant is essential in containing the infection.
Another factor to consider is viral infection. Mosaic viruses are particularly common in green beans. These are caused by aphids, which spread the disease from plant to plant. Two different mosaic viruses in green beans are the bean common mosaic virus (BCMV) and the bean yellow mosaic virus (BYMV). These two diseases are common, so it’ll do a lot of good to carefully inspect your plants.
BCMV can be seen in an irregular mosaic pattern on the leaves, manifesting as light yellow and green. The leaves can also pucker and warp, which causes them to roll in on themselves. The disease stunts the growth of the plant, and eventually results in its death. This virus is usually less of a problem these days because of the disease-resistant varieties of green beans that have been developed in recent years.
BYMV can manifest similarly to BCMV, as both have the mosaic pattern on the plant’s foliage. However, you should notice more yellow spots on the plant, as well as drooping leaflets. Leaves will also curl in on themselves, and may turn stiff and/or glossy. As in BCMV, the plant’s growth will become stunted, and death comes for it soon enough.
How to Fix:
Unfortunately, in both cases, you will need to destroy the plants to prevent further spread among your other green bean crops. There are a few measures to take when planning for future plants. You should always purchase seeds from a reputable source, taking care to ensure that you purchase a variety of seeds that is disease-resistant.
Since aphids are the worst spreaders of these viruses, keep them in check with insecticidal soap or other pesticides– just be sure these are safe to use on plants where the yield will be eventually eaten. Neem oil also works well in this case.
As a bonus, let’s also consider acclimation as a reason for your green bean plant’s yellowing. When buying an established plant, it’s fairly common for them to be a bit dramatic when introduced to their new home.
The plant will be used to the conditions in their previous environment, likely a warm greenhouse, so an unfamiliar environment can cause them some distress. This can manifest as leaves yellowing, as well as the death of lower leaves and general droopiness. A few days in its new spot should perk it back up!
Remember that green beans are annual plants, and will complete their life cycle in a single year. The reason for your green bean’s leaves turning yellow could be because it’s simply that time in their life cycle. When this happens, usually at the turn of the seasons, it’s time to let the plant rest. Thank it for its service, and for all the wonderful green beans you’ve harvested over the summertime!
We hope that this article has helped answer your questions about your green bean plant’s leaves turning yellow. While it takes some effort on your part to get to the root of the issue, it’s worth the trouble to save your plants and ensure that they are producing beans at a good rate.
Applying the solutions to your plant’s problems can really make a world of difference in less time than you might expect.