If you’re noticing yellow leaves on your geraniums, you’re not alone. This is a very common issue, and figuring out why are my geranium leaves turning yellow is the first step to fixing it. Don’t worry, most causes are simple to correct once you know what to look for.
Geraniums are tough plants, but they give us clear signals when something’s off. Yellowing leaves, called chlorosis, can be caused by water issues, light problems, nutrient needs, or pests. The good news is that with a few adjustments, you can often have your plants back to their green, vibrant selves in no time.
Let’s look at the most common reasons and their simple solutions.
Why Are My Geranium Leaves Turning Yellow
The key is to observe where the yellowing is happening and what else is going on with the plant. The pattern of yellowing is your best clue. Is it the lower leaves, the new growth, or is it all over? Check the soil and think about your recent care routine.
1. Overwatering: The Most Common Culprit
Geraniums prefer to dry out a bit between waterings. Their roots need air, and constantly wet soil suffocates them, leading to root rot. The first sign is often yellowing leaves, usually starting with the lower, older leaves.
* Signs: Leaves are yellow, often limp or mushy. The stems may feel soft or look darkened. The soil stays wet for days.
* Solution:
1. Stop watering immediately. Let the soil dry out completely.
2. Check the drainage holes in your pot to ensure they’re not blocked.
3. If the plant is severely wilted or the stem is soft, gently remove it from the pot. Trim away any black, mushy roots with clean scissors.
4. Repot in fresh, well-draining potting mix and a clean pot with drainage holes.
5. Going forward, water only when the top inch or two of soil feels dry to the touch.
2. Underwatering: The Other Extreme
While they dislike soggy feet, geraniums still need water to thrive. Severe drought stress will also cause leaves to yellow and then turn crispy brown.
* Signs: Leaves are yellow or brown, dry, and brittle. The entire plant may look wilted, and the soil is pulling away from the edges of the pot.
* Solution: Give the plant a thorough, deep watering. Water until it runs freely from the drainage holes. For potted plants, you might need to soak the pot in a basin of water for 30 minutes if the soil has become water-repellent. Then, return to a more consistent watering schedule.
3. Lack of Sunlight
Geraniums are sun-lovers. They need at least 4-6 hours of direct sunlight daily to produce strong growth and vibrant blooms. In too much shade, they become leggy and their leaves can start to pale and yellow.
* Signs: Overall pale or yellowing leaves, especially on new growth. The plant stretches out with long spaces between leaves.
* Solution: Gradually move your geranium to a sunnier location. A south- or west-facing spot is ideal. If growing indoors, a bright windowsill is best. If natural light is limited, consider using a grow light to supplement.
4. Nutrient Deficiency: Hungry Plants
Geraniums are moderate feeders, especially when blooming heavily. A lack of key nutrients, particularly nitrogen, iron, or magnesium, can cause yellowing.
* Nitrogen Deficiency: Older, lower leaves turn uniformly yellow.
Iron Deficiency: New leaves turn yellow between the veins, which stay green.
* Magnesium Deficiency: Older leaves show yellow patches between the veins.
* Solution: Feed your geraniums with a balanced, water-soluble fertilizer (like a 20-20-20) or one formulated for flowering plants. Follow the label instructions—over-fertilizing can also cause problems! For a quick fix for iron or magnesium, you can use a specialized supplement.
5. Poor Soil Drainage or Compacted Soil
Even with perfect watering, if the soil doesn’t drain well, the roots will sit in moisture. This is essentially the same problem as overwatering.
* Signs: Similar to overwatering: yellow leaves, slow growth, soil that stays damp.
* Solution: For garden beds, amend heavy clay soil with compost or coarse sand to improve drainage. For container plants, always use a high-quality potting mix, not garden soil. Ensure pots have adequate drainage holes.
6. Temperature Stress and Poor Air Circulation
Geraniums enjoy warm days and cooler nights. Extreme heat can stress them, causing leaf yellowing and dropped buds. Cold drafts or chilly nights below 50°F (10°C) can also cause problems. Stagnant, humid air encourages fungal diseases.
* Signs: Yellowing or reddening of leaves, leaf drop, general poor growth.
* Solution: Protect plants from sudden temperature swings. Provide good air flow around them by not crowding plants together. Prune out some inner stems if the plant is very dense.
7. Pests and Diseases
While less common, some bugs and fungi can cause yellowing.
* Spider Mites: Tiny pests that cause stippled yellow leaves and fine webbing. Spray with insecticidal soap or a strong jet of water.
* Whiteflies: Small white insects that flutter up when disturbed, leading to yellowed, sticky leaves. Use yellow sticky traps and insecticidal soap.
* Fungal Diseases (like Rust or Botrytis): Cause spotted yellowing or gray mold. Remove affected leaves immediately, improve air circulation, and avoid wetting the foliage when watering.
8. Natural Aging of Lower Leaves
Sometimes, there’s nothing wrong at all! It’s normal for the oldest leaves at the very bottom of the plant to gradually turn yellow and drop off as the plant grows. This is just the plant’s way of focusing energy on new growth.
* Signs: Only one or two of the very bottom leaves are yellowing, and the rest of the plant looks healthy and vigorous.
* Solution: Simply pinch or snip off the yellow leaves to keep the plant looking tidy and to prevent any potential disease from starting there.
Your Step-by-Step Diagnostic Checklist
Follow these steps to find the cause:
1. Check the Soil Moisture. Is it sopping wet, bone dry, or just right?
2. Look at the Leaf Pattern. Are lower, upper, or all leaves yellow? Are there spots or is it uniform?
3. Inspect for Pests. Look closely under leaves and along stems for tiny bugs or webbing.
4. Review Your Care. When did you last fertilize? Has the weather been extreme? Have you moved the plant recently?
5. Examine the Roots (if needed). Gently check for root rot if overwatering is suspected.
Prevention is the Best Medicine
To keep your geranium leaves from turning yellow in the first place, follow these basic tips:
* Use pots with drainage holes and quality potting mix.
* Water deeply, then allow the soil to dry partially before watering again.
* Provide plenty of bright, direct sunlight.
* Fertilize regularly during the growing season (spring through summer).
* Deadhead spent blooms and remove yellow leaves promptly.
* Ensure good air flow around your plants.
FAQ: Quick Answers to Common Geranium Questions
Q: Should I remove yellow leaves from my geranium?
A: Yes, it’s a good idea. Gently pinch or snip them off. This improves appearance, helps prevent disease, and allows the plant to direct energy to healthy growth.
Q: Can yellow geranium leaves turn green again?
A: Unfortunately, once a leaf turns yellow, it will not regain its green color. The goal is to correct the problem so that new growth comes in healthy and green.
Q: How often should I water my geraniums?
A: There’s no fixed schedule. The best method is the “finger test.” Water only when the top 1-2 inches of soil feels dry. This might be every few days in hot sun, or once a week in cooler weather.
Q: What is the best fertilizer for geraniums?
A: A balanced, all-purpose fertilizer or one slightly higher in phosphorus (the middle number) to promote blooming works well. A slow-release fertilizer applied at planting can also provide steady nutrients.
Q: Why are my geranium leaves turning yellow with brown spots?
A: This often indicates a fungal issue like rust or a bacterial problem. Immediately remove affected leaves, avoid overhead watering, and treat with an appropriate fungicide if neccessary. Improving air flow is crucial.
Remember, gardening is a process of observation and adjustment. Don’t be discouraged by a few yellow leaves—they’re your plant’s way of talking to you. By systematically checking the common causes, you can usually diagnose and solve the problem quickly, getting your geraniums back to their best.