Why are my geranium leaves turning yellow? Every concerned gardener is worried when they notice yellow leaves that should be green.
There are possible causes of this, which include incorrect variety, watering issues, malnutrition, inadequate light, extreme cold weather, diseases, pests, herbicide damage, and compacted soil.
Contents
Why Are the Leaves of My Geranium Plants Turning Yellow?
The leaves of your geranium are turning yellow because of several reasons.
It might be because of the variety or because there are essential needs of the plant that are not being met. It could also be a role played by the variety of the plant.
1. Inherent Characteristics of the Variety
Geraniums commonly refer to two different plant varieties: true geraniums, which belong to the Geranium genus, and Pelargoniums. These two are related, and both belong to the Geraniaceae family.
They look similar, and even though they require the same geranium care, true geraniums are hardy, whereas pelargoniums prefer it hotter.
This is important because they differ in why their leaves turn yellow. For Pelargoniums, it is natural for the older leaves to turn yellow; however, it may not be very noticeable if the plant is outdoors because a lot of newer leaves can cover the old ones. For true geraniums, if the leaves turn yellow, it is a signal that something is amiss with the plant.
2. Watering Issues
One of the most common problems with any plant is improper watering. For geraniums, yellow leaves can be a sign of this problem. There are only two possible scenarios: either the plant is receiving too much water compared to what it needs, or it is lacking and can benefit from additional hydration.
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Overwatering
Given that this plant is more drought-resistant, you might be overwatering it without realizing it. If the yellow leaves seem to be appearing more towards the base of the plant and some of the leaves have pale water spots on them, then the most probable cause is overwatering because these two are clear indications of it.
Overwatering will not only cause yellow leaves. Given that it will make the soil sit on the water, it can lead to several issues, such as root rot, pest infestations, or fungal infections.
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Underwatering
If the yellowing of the leaves is only along the margins, your plant might be experiencing a lack of water. Even though they are drought-resistant, if they don’t receive enough water, the leaves can turn yellow because of stress.
3. Lacking Nutrients
The leaves of your geranium may start to turn a light shade of green or yellow if you have been cultivating it in a small container or if it has been planted in the same location for several years. Its lack of necessary nutrition is the most likely reason for this.
However, in this case, it is quite challenging to determine the specific nutrient that the plant is lacking. It is because different nutrient deficiencies cause symptoms that start the same way, like the yellowing of the leaves.
For example, nitrogen deficiency also has the same effect as overwatering, which makes the lower leaves turn yellow. However, there is an additional sign of browning of the tips, which gradually spreads to the entire leaf.
Another nutrient deficiency that includes yellowing of the leaves is a zinc deficit. The leaves will turn yellow first, then fade to purple color. If the yellowing is around the veins and leaf margins, especially on older leaves, it is a magnesium deficiency.
4. Not Meeting Sunlight Requirements
Geranium plants require about 4 to 6 hours of direct sunlight every day. Especially for growing geraniums, if these plants do not receive the needed sunlight, it may result in the yellowing of the leaves.
5. Climate – Cold Snaps
Because geraniums are sun-loving plants, they like the warm weather and struggle when the temperature falls too low. Long-term exposure to cold or damp weather, especially freezing conditions, can result in the yellowing of its leaves.
6. Diseases
One of the reasons your plant has yellow leaves is not just because it is lacking nutrients, overwatered, or because of cold snaps. Simply put, it might be suffering from one of the below diseases.
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Fungal Infections
Fungal disease is a significant problem when it comes to geraniums, as it can be fatal if not treated early. Several kinds of fungi-related diseases make their leaves turn yellow, and we have listed them here.
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Alternaria leaf spot
Symptoms on leaves include having dark brown, irregularly shaped dots, with sizes ranging from unnoticeable to around 0.33 inches in diameter. Larger spots may contain multiple dark, concentric rings. The spots could also have a wide yellow halo surrounding them.
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Bacterial blight
One of the most serious diseases that can affect geraniums is bacterial blight or bacterial leaf spot. In general, the illness is referred to as a spot as long as the spots are clearly divided from one another by green tissue.
The illness is referred to as a blight when these patches appear abruptly and combine to produce a bigger mass of damaged tissue. It is a vein-ending yellowing of the leaves, often in the shape of the letter V.
Wilting and yellow spots are the results of bacterial blight, which begins at the base of the plant. As it progresses, it can cause stem rot and ultimately harm the entire plant.
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Verticillium wilt
The lower and center leaves of geraniums will begin to wilt before turning yellow and dropping off. Stunted plant growth is possible as well.
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Viral Infections: Southern Bacterial wilt
This viral infection shares many of the same symptoms as blight; however, it always starts in the soil and progresses upward. It discolors the plant as it goes up. Although southern bacterial blight always causes these symptoms to move upward from the soil line, the lower parts of the plant will still turn yellow and wilt.
7. Pests Infestations
While bug infestations don’t cause a noticeable change to the color of the leaf, they can cause yellow, brown, or black spots as the pest consumes the leaf’s sap and causes it to become dehydrated. The easiest way to identify an infestation is by simply spotting the pests, most of which prefer to hang around on the undersides of leaves.
8. Herbicide damage
Herbicides and pesticides are helpful when it comes to controlling weeds; however, they can also harm your geranium by bleaching the leaves. Yellowing leaves and a burned or scorched appearance of the leaves (sometimes browned leaves) are indications of this.
9. Compact Soil
If you’ve already checked all of the above and still can’t figure out what’s causing the leaves of your geranium to turn yellow, the culprit might be the compacted soil, which causes the roots of the plant to be damaged, resulting in the incomplete absorption of nutrients by the plant and the yellowing of the leaves.
How Can You Solve the Yellowing of the Leaves of a Geranium Plant?
You can solve the yellowing of the leaves of a geranium plant by taking into account the variety, ensuring that the watering schedule and amount is correct, making sure that the plant is not lacking in essential nutrients and are not infested with pests.
1. Inherent Characteristics of the Variety
As mentioned the two types of geraniums have different reasons for yellowing leaves. If your pilargoniums are turning yellow you can know it’s due to age. That you can’t do anything about but if your true geranium has yellowing leaves you should consider the possibility that something is wrong. You can use the solutions below.
2. Watering Issues
It is critical to only water your geraniums when necessary. If you suspect that they are overwatered, stop the watering right away, and wait until the soil completely dries off. Given that geraniums are drought-resistant plants, they do not tolerate excessive amounts of water.
On the other hand, if you see signs of underwatering, it is best to check the soil first. To do this, simply insert your finger one inch below the topsoil, and if the soil feels dry, then it’s time to water the plant.
Watering geraniums is best done at the plant’s base, away from the foliage. This will lessen the risk of fungus infection. Make sure the soil gets a good soak and the root ball is moistened when you water your geraniums.
3. Lacking Nutrients
Utilizing fertilizers as a supplement is the best way to address nutrient deficiencies. During the growing season, geraniums should typically receive fertilizer twice a month instead of monthly. You can use liquid fertilizers or slow-release pellets as long as you follow the instructions on the container.
Making sure that the plant receives enough magnesium. As one of the crucial secondary minerals that have a direct effect on chlorophyll, magnesium is crucial because the plant’s chlorophyll, which is responsible for the green pigment, is directly tied to the yellowing of the leaves.
If your fertilizer is deficient in magnesium, you can simply spray your plants with diluted Epsom salts. Once the problem is located, altering the fertilizer or feeding schedule usually takes care of it.
4. Not Meeting Sunlight Requirements
The only solution to this problem is to expose your plant to direct sunlight. As geraniums require six hours of direct sunlight every day, if the plant is indoors, make sure to place it near a window that gets plenty of sunlight.
But if geraniums are grown outdoors, it is best to expose them to the morning sun because the plant will dry out more quickly in the afternoon when it is warmer. In short, morning full sun and afternoon shade are ideal conditions for growing geraniums outside.
5. Climate – Cold snaps
As geraniums are sun-loving plants, cold and frost are their weaknesses. If they are planted in a pot outdoors, it may be necessary to cover them with a frost cloth or bring them inside to protect them from the cold. They should not be planted outside until all danger of frost has passed.
6. Diseases
Depending on the severity, some infections can still be treated with fungicides. However, others that had a severe impact leave you with no other options but to destroy the affected plants.
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Fungal Infections
Generally speaking, all can be treated with a fungicide. Once it is confirmed that you have a diseased plant, treat it with fungicide as soon as possible. At first, this can be done weekly.
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Alternaria leaf spot
Avoid watering from above. Crop waste should be removed and destroyed from walks, pots, and seats. Use a fungicide to safeguard plants.
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Bacterial blight
Infected plants should be thrown away, and good hygiene practices should be followed with everything that may have come into contact with the diseased geranium, including potting tables and gardening tools.
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Verticillium wilt
Purchase cuttings with a cultivation index. Employ sterile potting soil. Remove the diseased plants.
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Viral Infections: Southern Bacterial wilt
Purchase plants with cultivation indexes. Ground-planted geraniums should not be brought into the production area or multiplied from them. Eliminate the diseased plants.
7. Pests Infestations
Every two to three weeks, give your plant a regular dose of neem soil soak to treat any current infestations and help prevent new ones.
8. Herbicide Damage
The best way to address herbicide damage is to remove any affected leaves from the plant. If the damage is significant, you might need to trim the plant to encourage new growth. Be careful to water the plants well and give them extra care while they mend after removing the damaged leaves.
To prevent this from happening again, instead of using herbicides, which can unintentionally harm your geraniums, use a mulch to control the weeds surrounding your plants.
9. Compact Soil
Be mindful that poor soil drainage may also cause overwatering, which in turn can result in the yellowing of the leaves. It’s typically a good idea to have a gravel substrate beneath the planting layer.
Gravel can also be added to the bottom of containers. The soil should also have a small amount of aggregate added to it, preferably perlite, though coarse sand is also a great option.
These will prevent the soil from being overly compacted and ensure that there are a few small air pockets.
Conclusion
A plant with yellow leaves is a clear indication that the plant is having issues or is not healthy at all. Let us summarize what we have discovered:
- Pelargoniums, which are often mistaken for true geraniums, have yellowing leaves. It does not indicate a problem as this is a natural occurrence\.
- Geraniums are susceptible to cold and frost; thus, it is not advisable to put them outdoors when there is still a possibility of frost.
- Diseases and pests can usually be solved by using fungicides and pesticides.
- However, if your plant has blight disease, it’s best to eliminate the affected plants to prevent the disease from spreading.
- All other causes, like watering issues, malnutrition, inadequate light, and compacted soil, can be addressed by understanding the plant’s needs.
With all of the lessons learned here, there is no need to worry when you encounter the yellowing of the leaves of your geraniums. As you already know how to solve it, you can now take better care of your geranium plants.
References:
- https://portal.ct.gov/CAES/Fact-Sheets/Plant-Pathology/Diseases-of-Geranium
- https://ag.umass.edu/greenhouse-floriculture/photos/geranium-bacterial-leaf-spot-pseudomonas-syringae
- https://plantpath.ifas.ufl.edu/rsol/trainingmodules/SWGeranium_Module.html
- https://extension.psu.edu/geranium-diseases
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