If you’ve noticed your geranium leaves turning red, you’re likely wondering what it means. This color change is a common sign of plant stress, and understanding the cause is the first step to helping your plant recover.
Seeing red leaves can be surprising, but don’t panic. Geraniums often use color to communicate. While some varieties naturally have red or purple tints, a sudden shift to red, especially on the edges or undersides of leaves, usually signals that something in its environment is off. Let’s look at the reasons why and what you can do about it.
Geranium Leaves Turning Red – Sign Of Plant Stress
This specific symptom is your plant’s way of telling you it’s not entirely happy. The red pigment, called anthocyanin, is produced by the plant as a protective response to various stressors. It’s like a sunburn or a warning light on your car’s dashboard.
Primary Causes of Red Leaves on Geraniums
Several key factors can trigger this stress response. Identifying the correct one is crucial for fixing the problem.
1. Temperature Stress (Too Cold)
This is one of the most frequent causes. Geraniums prefer warm conditions and are sensitive to cold.
- When temperatures drop, especially at night, the plant produces more anthocyanin to protect its cells.
- You’ll often see reddening on the leaf edges and stems first.
- This is very common in early spring or late fall when there’s a sharp temperature fluctuation.
2. Light Intensity (Too Much Sun)
While geraniums love sun, sudden exposure to intense, direct light can cause a sunburn-like effect.
- New plants moved directly outdoors or indoor plants placed in a blazing south-facing window are prone to this.
- The red color acts as a natural sunscreen, but if the light is too harsh, leaves may also become crispy or bleached.
3. Nutrient Deficiencies
A lack of essential nutrients, particularly phosphorus, can lead to red or purple leaves.
- Phosphorus is vital for energy transfer within the plant. When it’s lacking, sugars can build up and trigger anthocyanin production.
- This often happens in cool, wet soil where roots can’t absorb phosphorus efficiently, even if it’s present in the soil.
- Other deficiencies, like magnesium, can sometimes contribute.
4. Watering Issues
Both under-watering and over-watering create stress that can manifest as red leaves.
- Under-watering causes general stress, making the plant more susceptible to other issues like sun scorch.
- Over-watering leads to root rot, which damages the roots and prevents them from taking up water and nutrients properly, leading to multiple deficiency symptoms.
5. Root Restriction
A pot-bound geranium has outgrown its container.
- Cramped roots can’t support the plant’s needs, leading to stress and nutrient uptake problems.
- Check if roots are circling densely at the bottom of the pot or growing out of the drainage holes.
Step-by-Step Diagnosis and Fix
Follow these steps to figure out the cause and save your geranium.
Step 1: Assess the Environment
Look at where your plant is living. Check the recent weather. Have their been cold snaps or unseasonably cool nights? Has it been suddenly very sunny? Evaluate the light exposure—is it getting more than 6-8 hours of hot, direct sun?
Step 2: Check Your Watering Habits
Feel the soil. Is it bone dry several inches down, or is it constantly soggy? Geraniums like the soil to dry out somewhat between waterings. Stick your finger in the soil; if it’s wet below the surface, hold off on watering. If it’s very dry, give it a thorough soak until water runs out the bottom.
Step 3: Inspect the Roots and Pot
If water issues are suspected, gently tip the plant out of its pot. Look at the roots. Healthy roots are firm and white or light tan. Rotten roots are mushy, slimy, and dark. Also note if the root ball is a tight mass with little soil visible.
Step 4: Consider Feeding Schedule
When was the last time you fertilized? Have you been using a balanced fertilizer? In cool soil conditions, a deficiency can occur even if you’ve fed the plant recently.
Solutions for Each Cause
For Temperature Stress:
- Move potted geraniums to a warmer location, like closer to a house wall, or bring them indoors if frost is expected.
- Use a cloche or frost cloth to protect garden plants from cold nights.
- The red color should fade as temperatures consistently warm up.
For Too Much Sun:
- Provide afternoon shade for plants in intensely hot climates.
- Acclimate indoor-started plants to full sun over 7-10 days, increasing exposure gradually.
- Sheer curtains can help filter light for indoor plants in south-facing windows.
For Nutrient Deficiency:
- Apply a balanced, water-soluble fertilizer (like a 10-10-10 or 20-20-20) according to label instructions.
- If soil is cold and wet, let it dry and warm up first; the plant may then access existing phosphorus.
- For a quick boost, a liquid fertilizer is absorbed faster than a granular one.
For Watering Problems:
- Establish a consistent watering routine: water deeply when the top inch of soil is dry, then let it drain completely.
- Ensure pots have drainage holes. Never let them sit in a saucer of standing water.
- For over-watered plants with root rot, trim away blackened roots, repot in fresh, well-draining soil, and reduce watering frequency.
For a Pot-Bound Plant:
- Repot your geranium into a container that is only 1-2 inches larger in diameter.
- Use a high-quality potting mix designed for containers.
- Gently loosen the outer roots before placing it in the new pot.
Prevention is Key
Keeping your geraniums healthy from the start prevents stress. Here’s how:
- Plant them in well-draining soil. Amend garden beds with compost if needed.
- Choose a location with at least 6 hours of morning sun, with some afternoon protection in very hot zones.
- Fertilize regularly during the active growing season (spring through early fall), but stop in winter when growth slows.
- Water at the base of the plant, avoiding the leaves, to prevent fungal diseases.
- Protect them from early and late season frosts. They really don’t like the cold.
Remember, a few red leaves doesn’t mean your plant is dying. It’s a resilient communicator. Once you correct the underlying issue, new growth should emerge green and healthy. The existing red leaves may not revert back to green, but you can snip them off if you prefer as the plant recovers.
FAQ: Geranium Leaves Turning Red
Is it always bad if geranium leaves turn red?
Not always. Some geranium varieties, like many fancy-leaf or ivy types, naturally have red, bronze, or purple foliage. Stress-related reddening is usually accompanied by other clues, like cool weather or rapid growth changes.
Can too much fertilizer cause red leaves?
Over-fertilizing can cause salt buildup in the soil, which damages roots and leads to stress symptoms that might include red leaves. It’s more likley to cause brown leaf tips, but it can contribute to overall poor health.
Should I remove the red leaves?
You don’t have to. They are still functional for the plant. If you find them unsightly, you can prune them off once the plant is showing healthy new growth. Avoid removing more than a third of the foliage at once.
Will the red leaves turn green again?
Typically, no. The red color in stressed leaves is often permanent. The goal is to correct the problem so that the new leaves produced are a healthy green color. The plant will eventualy outgrow the old, red leaves.
My geranium is indoors and its leaves are turning red. Why?
Indoor geraniums can experience temperature stress from cold drafts near windows or from air conditioning vents. They can also get too much intense light through a glass window, or suffer from nutrient depletion in potted soil that hasn’t been refreshed.
By paying attention to your geranium’s leaves, you become a better plant caretaker. That red hue is simply it’s way of asking for a small change. With a little observation and these simple steps, you can have your geranium back to its vibrant, flourishing self in no time.