“Why are my geraniums turning yellow despite my usual care routine?” – This question is just so common for geraniums growers, since it is an easily emerging problem.
Garden geraniums (Pelargonium spp.) are well-known for their vibrant colors and easy-to-grow nature.
You're reading: Why Are My Geraniums Turning Yellow: 8 Potential Causes
While many people associate these flowers with outdoor beds and containers, several types of geraniums also thrive as houseplants.
In this article, we will explore the most ubiquitous reasons why geranium leaves turn yellow and discover the best steps to rectify the issue.
1. Understanding Yellowing Leaves
Yellow leaves can be a natural part of the aging process for geraniums that are a year or older.
As geraniums grow, they develop woody stalks and shed their lower leaves. In this case, yellowing foliage is nothing to worry about.
However, more often than not, yellowing leaves on potted geraniums indicate a problem with the plant’s health or environment.
Plant foliage appears yellow when it lacks sufficient chlorophyll, a condition known as chlorosis.
Nutrient deficiencies and diseases are common culprits for this symptom.
Additionally, cultural factors such as improper watering, cool temperatures, or inadequate sunlight can also cause chlorosis in geraniums.
2. Over or Underwatering
Overwatering is the primary cause of yellow leaves in most houseplants, including geraniums.
Signs of overwatered geraniums include yellow leaves accompanied by drooping flower stalks.
On the other hand, underwatered geraniums typically exhibit yellow leaf margins with a dry texture.
To differentiate between the two, it’s essential to examine the moisture level of the soil.
Unfortunately, the yellowing caused by overwatering is often mistaken for underwatering, exacerbating the issue.
Key watering principles for geraniums:
- Depending on the pot size, allow the soil to dry out up to 6 inches deep before watering.
- If your geranium shows signs of dehydration, reassess your watering schedule and household humidity.
- Adding organic material to the potting soil can improve moisture retention without compromising drainage.
- Potted geraniums are prone to overwatering.
- Geraniums are drought-tolerant flowers that prefer their soil to dry out between waterings.
3. Poor Drainage Container
Ensure that your geraniums are planted in containers with proper drainage holes and well-draining soil.
Avoid placing indoor geraniums in saucers that can collect standing water.
If you suspect overwatering, move the plant to a bright, warm location to facilitate drying.
Withhold additional water until the geranium shows signs of recovery and check if the container is draining properly.
4. Low Temperatures
Geraniums thrive in daytime temperatures between 65 and 70°F, with nighttime temperatures above 55°F.
If you keep potted geraniums in areas like unheated covered porches or near drafty windows or AC vents, they may develop yellow leaves and other symptoms.
What You Can Do
Read more : How to Get Rid of Coneflower Mites and other Pests
To prevent this, relocate your geraniums indoors by early fall at the latest if you usually keep them outdoors during the summer.
In the spring, wait until nighttime temperatures consistently exceed 50°F before moving potted geraniums outdoors.
5. Insufficient Sunlight
One challenge of growing geraniums as houseplants is their need for direct sunlight.
Indoor geraniums require 6 to 8 hours of bright sunlight daily to remain healthy and produce abundant flowers.
Insufficient sunlight can cause geranium leaves to turn pale green or yellow.
This occurs because the plant senses the lack of light and conserves energy by reducing chlorophyll production.
What You Can Do
For optimal results, place potted geraniums near a bright window that receives direct sunlight throughout the day.
If you live in the Northern Hemisphere, an east- or south-facing window is ideal, while a north- or west-facing window suits those in the Southern Hemisphere.
If providing sufficient natural light is difficult, you can use a grow light above your geraniums.
Set the light to stay on for up to 14 hours daily, as grow lights are less intense than natural sunlight.
6. Nutrient Deficiencies
Nutrient deficiencies are rare in geraniums grown as annuals since they typically do not live long enough to display visible symptoms.
However, houseplants, including geraniums, may experience nutrient deficiencies.
The most common deficiencies that cause chlorosis in potted geraniums are nitrogen and potassium.
Iron, zinc, manganese, and sulfur deficiencies may also lead to yellowing leaves.
Nutritional imbalances usually manifest as yellowing leaf margins. A nitrogen deficiency can cause purple discoloration along leaf veins as well.
What You Can Do
A balanced feeding regimen is the best way to prevent nutrient deficiencies in geraniums.
Use a slow-release fertilizer formulated for houseplants or a diluted liquid formula.
Feed geraniums once or twice per month during the growing season, adjusting the frequency according to the fertilizer’s instructions.
Reduce or withhold fertilizer during the winter when growth naturally slows.
7. Pests and Disease
While no unique pests specifically target indoor geraniums, it’s crucial to watch out for common plant pests when growing geraniums as houseplants.
Aphids and spider mites are often responsible for yellow foliage. These pests feed by piercing and sucking liquid out of the leaves, resulting in countless yellow spots.
What You Can Do
Read more : Pansy vs Petunia: Unraveling the Charms of Your Garden’s Perfect Flower
To control aphids and spider mites, use horticultural oil or insecticidal soap.
Mild infestations can be resolved by spraying clean water on the geranium’s foliage.
Isolate infested plants to prevent the pests from spreading to other pots.
8. Disease
Geraniums are susceptible to several diseases that can cause yellow leaves. Here are a few examples:
Bacterial Blight
Blight (Xanthomonas campestris pv. pelargonii) is a common problem, particularly affecting geraniums.
It is identifiable by small watermarked indentations on the leaves, up to 1/4 inch in size, which eventually spread and kill the leaf.
The disease is carried in soil and on surfaces, making it necessary to dispose of infected plants.
Image source: The Little Garden
Verticillium Wilt
Verticillium wilt (Verticillium albo-atrum) causes yellowing and drying of leaves, starting from the base of the plant.
Most cases of verticillium wilt, especially in houseplants, occur due to infected soil.
Southern Bacterial Wilt
Southern bacterial wilt (Ralstonia solanacearum) causes the lower leaves of geraniums to wilt, turn yellow, and drop prematurely.
This bacterium is often transmitted when in-ground plants are moved indoors.
Your geranium may have been exposed to these diseases in its original greenhouse or plant nursery. Contaminated soil or new houseplants can also introduce diseases.
FAQ – Yellow Leaves on Geraniums
Is it ok if geranium leaves at the bottom are turning yellow and dying?
Chances are, the main culprit here is how you’re watering your geraniums. When you give them a drink, make sure the whole pot gets soaked, not just the top layer of soil.
Are red leaves on geraniums normal?
When geranium leaves turn red, it’s like a stress signal from your plant. This crimson hue usually points to minor problems such as over or underwatering, nutrient shortages, or the chill of cool temperatures.
Why are the leaves of my geraniums turning light?
Nitrogen deficiency is most likely the reason behind this phenomenon.
Why are the leaves on my geraniums turning brown?
Most of the time, it is an indicator of wrong watering frequency, but there are other possibilities as well.
Final Thoughts on Geranium Leaves Turning Yellow
The numerous factors that can cause geranium leaves to turn yellow might seem overwhelming.
However, proper care is usually the key to addressing most potential causes.
Reevaluate the current maintenance routine whenever a houseplant develops yellow leaves.
Simple adjustments such as providing adequate light or adjusting watering habits may solve the problem.
If environmental factors are not to blame, consider nutritional deficiencies or infectious diseases as potential issues.
Prompt diagnosis and treatment are crucial for the successful recovery of your geranium, regardless of the underlying cause of its yellow foliage.
Citation:
- Utah State University – Verticillium Wilt
- Penn State Extension – Bacterial Blight of Geranium
Source: https://thelittle.garden
Category: Gardening