Why Are My Geranium Leaves Turning Yellow

If you’re noticing yellow leaves on your geraniums, you’re not alone. This is a common issue that many gardeners face. Let’s look at why are my geranium leaves turning yellow and how to fix it for good.

Geraniums are popular for their bright flowers and easy care. But yellow leaves can be a sign that something is off. The good news is that most causes are simple to correct once you know what to look for.

This guide will walk you through every possible reason. We’ll go from the most common issues to the less frequent ones. You’ll learn how to diagnose the problem and get your plants back to health.

Yellowing leaves, called chlorosis, is a symptom. It’s the plant’s way of telling you it’s stressed. The key is to look at where the yellowing starts and what other signs are present.

Are the older, lower leaves yellowing first? Or is it the new growth at the top? Are the leaves spotted, or uniformly yellow? The answers will point you to the root cause.

1. Overwatering: The Most Common Culprit

This is the number one reason for yellow geranium leaves. Geraniums prefer to dry out a bit between waterings. Their roots need air, and constantly wet soil suffocates them.

When roots are waterlogged, they can’t take up nutrients properly. They also start to rot. The first sign is often yellowing lower leaves that may feel soft or mushy.

How to Fix Overwatering

Check the soil before you water. Stick your finger about an inch deep. If it feels damp, wait.
Ensure your pot has excellent drainage holes. Saucers should not be left full of water.
Use a well-draining potting mix. Add perlite or coarse sand to heavy soil.
If the plant is severely overwatered, you may need to repot it into fresh, dry soil. Trim any black, slimy roots first.

2. Underwatering and Drought Stress

On the flip side, not enough water can also cause yellow leaves. A thirsty geranium will conserve resources. It will often sacrifice its older leaves, turning them yellow and crispy before they drop.

The entire plant may look wilted and the soil will be very dry. The leaves typically feel dry and brittle, not soft.

How to Fix Underwatering

Water deeply when you do water. Ensure water runs out the bottom of the pot, soaking the entire root ball.
Don’t just sprinkle the surface. This encourages shallow roots.
In hot, sunny weather, potted geraniums may need water every day. Adjust your schedule with the seasons.

3. Lack of Nutrients (Especially Nitrogen)

Geraniums are moderate feeders. If they’ve been in the same pot for a long time, they can use up the available nutrients. A lack of nitrogen is a classic cause of uniform yellowing, starting with the older leaves.

Nitrogen is mobile in the plant. When it’s scarce, the plant moves it from old leaves to support new growth. That’s why the older leaves turn yellow first.

How to Fix Nutrient Deficiencies

Feed your geraniums regularly during the growing season. Use a balanced, water-soluble fertilizer (like a 20-20-20) every 2-4 weeks.
For a quick green-up, you can use a fertilizer with a slightly higher nitrogen number (the first of the three numbers on the label).
If plants are in the ground, top-dress with compost or a slow-release granular fertilizer in spring.

4. Poor Soil Drainage

This is related to overwatering but focuses on the soil itself. Heavy, clay-based, or compacted soil holds too much water. Even if you’re watering correctly, the soil stays wet for too long.

Garden beds with poor drainage will cause the same root problems as overwatering in a pot.

How to Improve Soil Drainage

For pots, always use a quality potting mix designed for containers.
In garden beds, amend heavy soil with lots of organic matter like compost or well-rotted manure. This improves soil structure.
Consider planting geraniums in raised beds if your native soil is very dense and poorly draining.

5. Insufficient Sunlight

Geraniums love sun. They thrive with at least 4-6 hours of direct sunlight per day, and more is better. In too much shade, they become leggy and their leaves can turn pale green or yellow.

The plant isn’t producing enough chlorophyll, which is what makes leaves green and drives photosynthesis. This yellowing is often general and affects the whole plant.

How to Fix Light Issues

Move potted geraniums to a sunnier location. A south or west-facing spot is ideal.
If growing indoors, place them in your brightest window. A east or south window is best.
Prune back any nearby plants that might be shading your garden geraniums.

6. Temperature Extremes and Cold Shock

Geraniums are warm-weather plants. Cold temperatures, especially frost, can damage leaves, causing them to turn yellow or red and then brown. Even a sudden cold draft indoors can cause stress.

Conversely, extreme heat combined with dry soil can also scorch and yellow leaves. This is usally a problem in the peak of summer.

How to Protect from Temperature Stress

Don’t plant geraniums outdoors until all danger of frost has passed in spring.
Bring pots indoors before the first fall frost.
In intense heat, provide afternoon shade and be vigilant about watering.
Keep indoor plants away from drafty windows and air conditioning vents.

7. Natural Aging Process

Sometimes, yellow leaves are no cause for alarm. It’s normal for the oldest, lowest leaves on a geranium to turn yellow and drop off as the plant grows.

This is just the plant’s way of shedding leaves it no longer needs. If it’s only one or two leaves at the bottom and the rest of the plant looks vigorous, it’s likely just natural aging.

What to Do About Natural Aging

Simply pinch or snip off the yellowed leaves to keep the plant looking tidy.
This also improves air circulation around the base of the plant.
No other action is needed if this is the only symptom.

8. Pests and Diseases

While less common, certain pests and diseases can cause yellowing leaves. It’s important to inspect your plants closely.

Look under the leaves and along the stems. Common culprits include spider mites, whiteflies, and aphids. Diseases like bacterial blight or rust can also cause yellow spotting.

How to Treat Pests and Disease

For pests like aphids or spider mites, spray the plant thoroughly with a strong stream of water to dislodge them.
Insecticidal soap or neem oil are effective organic treatments. Apply according to label instructions.
For fungal or bacterial diseases, remove and destroy affected leaves immediately. Improve air circulation and avoid wetting the foliage when you water.
In severe cases, a fungicide may be necessary. Always isolate an affected plant if possible.

9. Pot-Bound Roots

A geranium that has outgrown its pot can show signs of stress, including yellowing leaves. The roots have nowhere to grow, and they can’t take up water and nutrients efficiently.

You might see roots circling the surface of the soil or growing out the drainage holes. The plant may also dry out very quickly after watering.

How to Fix a Pot-Bound Plant

Gently remove the plant from its pot. If the roots are a dense, tangled mass, it’s time to repot.
Choose a new pot that is only 1-2 inches larger in diameter. Too big a pot holds excess moisture.
Loosen the root ball slightly with your fingers. Place it in the new pot with fresh potting mix.
Water well and return it to its sunny spot.

10. Incorrect Soil pH

Geraniums prefer a slightly acidic to neutral soil pH (around 6.0 to 7.0). If the soil is too alkaline (high pH), the plant cannot access certain nutrients, like iron, even if they are present in the soil.

This leads to a specific type of yellowing called iron chlorosis, where the veins stay green but the leaf tissue between turns yellow. It often shows on new growth first.

How to Adjust Soil pH

Test your soil pH with a home test kit or through your local extension service.
To lower pH (make more acidic), you can incorporate elemental sulfur or use a fertilizer for acid-loving plants.
For a quick fix for iron deficiency, you can apply chelated iron directly to the leaves or soil as directed.

Step-by-Step Diagnostic Guide

Follow this simple flowchart to pinpoint your problem:

Check the Soil Moisture: Is it sopping wet, bone dry, or just right? Wet points to overwatering/poor drainage. Dry points to underwatering.
Look at the Leaf Pattern: Are only lower leaves yellow? Think overwatering, underwatering, or natural aging. Is new growth yellow? Think nutrients or pH.
Inspect for Pests: Look closely under leaves and on stems for tiny bugs or webbing.
Consider the Season & Location: Has it turned cold recently? Is the plant in a dark corner? Could it be sunburned from a recent move?
Recall Your Care: When did you last fertilize? Have you repotted in the last year or two?

Prevention is the Best Medicine

Keeping your geraniums healthy from the start prevents most yellow leaf issues. Here’s your prevention checklist:

Plant in the Right Spot: Full sun and well-draining soil are non-negotiable.
Water Wisely: Water deeply, then let the top inch of soil dry out. Use the finger test.
Feed Regularly: A consistent feeding schedule during growth periods keeps nutrients available.
Provide Good Drainage: In pots, use pots with holes and quality mix. In ground, amend soil.
Keep Them Clean: Remove dead leaves and spent flowers to encourage air flow and discourage disease.
Check Often: Regular quick check-ups help you spot a problem early, when it’s easiest to fix.

FAQ Section

Should I remove yellow leaves from my geranium?
Yes, it’s a good idea. Gently pull or snip them off. This makes the plant look better and helps prevent potential disease issues on the dying tissue.

Can yellow geranium leaves turn green again?
Once a leaf turns yellow, it will not turn back green. The chlorophyll is gone. Your goal is to correct the problem so that new growth comes in healthy and green.

What is the best fertilizer for geraniums to prevent yellowing?
A balanced, all-purpose fertilizer works well. Look for a water-soluble type with equal numbers (like 10-10-10 or 20-20-20) or one formulated specifically for flowering plants.

How often should geraniums be watered?
There’s no single schedule. It depends on heat, sun, pot size, and soil. Always check the soil first. It’s better to water based on need than on a rigid calendar.

Why are the leaves on my geranium turning yellow with brown spots?
This combination often suggests a fungal disease or sometimes bacterial issue. Remove affected leaves immediately, avoid overhead watering, and consider a fungicide if it spreads.

Is Epsom salt good for yellow geranium leaves?
Only if the yellowing is due to a magnesium deficiency, which is not the most common cause. Epsom salt is magnesium sulfate. It’s better to use a complete fertilizer unless a soil test confirms a lack of magnesium.

Figuring out why your geranium leaves are turning yellow is like being a plant detective. Start with the simplest explanations—usually water, light, or food. By observing carefully and adjusting your care, you can usually solve the mystery and restore your geraniums to their lush, green, and blooming glory. Remember, consistent care tailored to their simple needs is the secret to keeping those leaves green all season long.