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Garden plants normally have bright, vibrant, green leaves that brighten up their environment. Yellowing leaves is a condition known as chlorosis, which happens when something is interfering with the chlorophyll in the plant.
Chlorophyll is the pigment that makes parts of plants, including the leaves, green. When the leaves turn yellow, the plant is letting you know that it needs help. You just need to determine what is causing the yellow leaves so that you can help the plant.
Can Yellow Leaves Turn Green Again?
After you notice your garden plants yellowing, they can’t normally turn green again. However, you can still save the plant, and its new leaf growth will be green. Yellow leaves are a sign of stress or illness, and it is caused by a number of different situations. If a leaf has a small amount of yellow starting to form due to a lack of nutrients, you may be able to help the plant and turn the leaves green again, but most of the time, once the leaves turn yellow, they won’t change back. Take a look at 12 reasons why your garden plans are turning yellow and what you can do about it.
Poor Nutrition
Sometimes leaves turn yellow because there is a nutritional deficiency. One example is when there isn’t enough nitrogen in the soil. If soil isn’t replenished with nitrogen regularly, it can leach away and cause leaves to turn yellow. However, you should test the soil before you grab a bag of fertilizer. Make sure it isn’t another cause.
Potential deficiencies include the following:
- Nitrogen: low nitrogen can cause leaves to yellow
- Potassium: causes edges of older leaves to yellow
- Magnesium: causes patches of yellow
- Iron: top foliage turns yellow
- Sulfur: turns young leaves yellow and spreads
Poor Watering
Improper watering, whether too much or too little, is the most common cause of yellow leaves. Overwatering is common, as people want to make sure that their plants have enough water. In this case, a lot of the leaves will usually turn yellow at the same time.
You can check to see if the soil is soggy under the surface. The problem is that the roots can’t breathe if they are too soggy, so leaves won’t get the moisture and nutrients from the roots that allow them to go through photosynthesis. It can also lead to root rot, which will kill plants quickly.
If the soil is soggy, you need to let it dry. Try to reduce the light to ease the stress on the plant, and keep temperatures warm. If the roots are healthy and firm, you will be okay. If your plant is potted, you might consider repotting it and increasing the air circulation. Monitor the soil until you see new growth on the plant, which is a sign of recovery. If you catch it early enough, your plant can recover, but otherwise, you need to wait for new growth.
Underwatering also prevents leaves from receiving the moisture and nutrients they need to thrive and undergo photosynthesis. You will notice that the soil is dry, and the plant has likely started wilting.
You can’t just pour water on it to fix the problem; start by checking the soil and water it as you normally would. It will take some time, but overwatering won’t fix a dried-out plant.
Wrong Lighting
Lighting is another factor that can cause leaves to turn yellow. This can come from too much light or too little light. When a plant receives too much light, it will dry out and possibly scorch the leaves.
However, too little light allows the leaves to remain hydrated by reducing photosynthesis, which lowers how much chlorophyll is in the leaves. The chlorophyll is what gives leaves their green color. You may even notice that the side facing away from the light has an issue, in which case you can turn the plant.
Fertilizer Issues
If you are growing plants in containers and using premium plant fertilizers, you probably don’t have a problem with soil pH. However, this is a common problem for plants growing outdoors in the ground. The pH of the soil is directly related to the plant’s ability to receive the nutrients it needs.
As the pH of the soil changes and moves up or down the scale, different nutrients are available. Most plants do best when soil is normal to slightly acidic, so the preferred pH range is 6.0 to 7.0. There are some that prefer a lower pH, but you need to check your plant and make sure that the pH is where it should be.
Pest Infestation
There are different types of sucking insects that attack plants from the inside and the outside. This includes the following pests:
- Mites
- Aphids
- Mealybugs
- Thrips
- Scale
- Whiteflies
They are often too small to see with the naked eye, but you can identify them by looking at how the plant responds. These pests are feeding on the sap from the plant, which the plant needs. The reaction is one of a decline in health, and leaves will turn yellow.
If you find that you have pests, you can usually wash the plant to get the insects off. You can use neem oil or a horticultural soap.
Disease
Another cause of yellow leaves is disease. Root diseases are common, especially in soil that doesn’t drain well. Roots can become diseased when the soil is too moist, which limits the ability of the plant to get the nutrients and moisture it needs to survive.
The roots can rot away, which leaves the plant without a way to feed. You will often see leaves that are yellowing and withering when the roots are diseased.
If you notice that your plant is under attack by a disease, you need to remove any infected leaves. You should isolate the plant so that it doesn’t spread, and make sure that you sterilize any gardening tools you use. Diseases can be contagious, and they can kill the surrounding plants as well.
Some diseases are viral, and they will show yellow blotchy patches. This type of disease is not curable, and you will need to remove and safely dispose of the plants. Other times, it is the result of another issue, and fixing the problem can potentially cure the plant.
Temperature Extremes
Leaves can turn yellow and fall off if the plant is exposed to temperatures that are colder than it can handle. It can also happen to house plants if they are near an air conditioning vent or a draft. If this is the cause, once the leaves are damaged, you need to move the plant. Make sure that it isn’t in the way of a draft or a cold blast of air, and keep plants in their preferred temperature range.
Leaves can also turn yellow from extreme heat. If your plant is exposed to extremely hot temperatures, it can easily become stressed. When this happens, the leaves will turn yellow and drop off the plant. The reason this happens is that the plants are water-stressed, and they can’t maintain the energy needs of the leaves.
Transplant Shock
When you transplant any plants, it is stressful for them. Even if you try to give them everything they need, it is going to be different from what they are used to. The important thing is to give the plant the care it needs while it is adjusting and recovering.
You shouldn’t fertilize, give it too much water, or move the plant around to different locations. You need to be careful with it, and let it recover. Once it does, it will start producing green leaves again.
The problem is that the plant needs time to root after it is transplanted. You won’t see new growth during this time, as it takes all of the plant’s energy to develop a root system and survive. The leaves may turn yellow or bronze, and you might see them rolling or curling.
Acclimatization
Acclimatization is the ability of a plant to adapt to a new environment. When you plant them, they can experience stress from their environmental conditions. This shows yellowing or wilted leaves and failure to thrive or stunted growth.
For example, when you move plants from a pot inside your house to your garden outside, they need to acclimatize. You need to do what you can to keep their conditions as similar as possible. Some people recommend taking the soil and the plant and placing it in the hole in the ground to give it the best possible chance.
There are a number of factors to consider, including levels of light, humidity, temperature, nutrition, and water. All of these will contribute to your plant’s ability to thrive in its environment.
Root Damage
There are several different factors that can lead to root damage. One was already addressed, which is overwatering. This can cause the roots to be unable to absorb moisture and nutrients that the plant depends on for survival.
Overly wet soil can also cause root rot, which is a disease of the roots. They can disintegrate and leave the plant without any ability to get nourishment or water.
Roots can also be damaged. If you have your plant in a container, it is usually because the container is too small. The roots have nowhere to go as they grow, which can lead to compacted roots. You can solve this problem by moving them to a larger container.
Outdoors, your plant’s roots can also become compacted. The soil might be compacted so that the roots have trouble spreading out in the way they need to. They won’t be able to get the oxygen, water, or nutrition that the plant needs for survival. When the roots can’t function properly, the plant will get yellow leaves.
You need to know how to recognize healthy versus rotting roots. Healthy roots are a whitish-yellow color. If they are rotting, they are dark and smell bad. In this case, you will need to prune the roots and loosen them and replant them if they are potted. Outdoors, you can aerate your soil. You should also add organic matter and organic mulch to the areas where you have problem roots.
Poor Drainage
It is always important that your plants are in soil with good drainage. When soil becomes saturated with water, the plants wilt and die because the roots can’t get air, nutrition, or moisture. The space between the soil particles normally has air, but it becomes filled with water.
The impact continues because the roots of plants will rot, and eventually, they will die. Look for roots that are dark and slimy, as this is a sign of root rot. You won’t have healthy organisms, such as earthworms and microorganisms, in your soil if it is too wet.
The best way to improve your soil drainage is to add organic materials, such as peat moss, compost, shredded bark, and more to the soil. Make sure that you work the soil until it drains at a moderate rate of at least one inch per hour.
Improper Soil pH
The pH level of the soil lets you know how acidic it is. Different plants require different acid levels, and they have different nutritional needs. The pH affects what nutrients are available in the soil. If the pH is too high or too low, a plant might not survive.
Your plant might have yellow leaves if the pH is off. You need to test it so that you can find out what to add to get the pH back where it belongs.
Final Words
When you have plants with yellow leaves, you will want to find out why. The yellow leaves are a sign that something is wrong. There are a number of different potential causes, so you need to investigate to find out what is going on. You may be able to save your plant if you act quickly.
Sources
- https://extension.umaine.edu/gardening/manual/soils/soil-and-plant-nutrition/
- https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/making-sure-soil-drains-well.htm
- https://extension.illinois.edu/blogs/extensions-greatest-hits/2007-08-28-yellow-leaves-can-indicate-plant-problems