Tomato Plants Turning Purple: Causes and Fixes

How to Fix Tomato Plants Turning Purple

Ever noticed your tomato seedlings turning an unexpected shade of purple? You’re not alone in this! 

The sight of purple tomato plants might raise concerns, but there’s no need to ring the alarm just yet. The thing is, we can most likely solve this!

So, let’s get hands-on and figure out why your tomato seedlings are sporting that cool but perplexing purple color.

Common Purple Tomato Sights

Purple Stems on Young Leaves

Purple Stems on Young Leaves
Image by YouTube
The Fix: Watch and Wait
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Picture those immature leaves about to develop into true leaves yet already revealing a touch of purple along their stems. Don’t worry, there’s absolutely no need for concern.

How to Watch and Wait
Monitor the plant and adjust accordingly.
You see, this is actually quite common, and these seedlings typically recover over time. While it might be tempting, it’s best to wait before applying any fertilizer right now.

Purple Bottom Leaves and Stems on Older Seedlings

Purple Bottom Leaves and Stems on Older Seedlings
Image by Gardener’s World Forum
The Fix: Adequately Feed Plants
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If you spot older tomato plants with leaves turning purple at the bottom, it’s likely they’re sending up a signal about needing more phosphorus. 

How to Adequately Feed Plants
1. Fertilize as needed.
Apply suitable plant food to your plants as directed. This uncomplicated process provides essential nutrients for their development.
2. Monitor and adjust accordingly.
Keep a watchful eye on the emergence of new leaves. This practice is key to tracking the effectiveness of the applied plant food and the overall health of your plants.

Purple Veins on the Back of Leaves

Purple Veins on the Back of Leaves
Image by Aggie Horticulture – Texas A&M University
The Fix: Apply Balanced Fertilizers
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Have you ever looked at the leaves of your tomato plant and noticed something interesting? Normally, the upper parts of the leaves are a lively green shade. 

However, if you sneak a look underneath, you might spot a deeper purple hue. Especially when your plants are over two weeks old, this might suggest they’re not getting all the vital nutrients they need. 

How to Apply Balanced Fertilizers
Pick a balanced fertilizer.
Choose a balanced fertilizer that provides equal proportions of essential nitrogen, phosphorus, and potassium (NPK) nutrients. Apply the fertilizer according to the manufacturer’s instructions. 
This is usually a straightforward process. Ensure the fertilizer is evenly distributed around the affected plants.

Purple, Rolled-Up Leaves on Older Seedlings

Purple, Rolled-Up Leaves on Older Seedlings
Image by Tiny Garden Habit
The Fix: Provide Adequate Plant Care
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EaseModerate ●●○○○
Maintenance LevelLow ●○○○○
Estimated CostsModerate ●●○○○
Possible RisksModerate ●●○○○

The tangled mix of purple, curled leaves shows there’s a problem. It’s mainly a blend of factors that can cause this, such as shifts in temperature, watering routines, sunlight exposure, and possibly excessive fertilizer usage. 

Even experienced gardeners might find it challenging to pinpoint the exact cause, so there’s no need to fret. You’re not the only one in this situation.

How to Provide Adequate Plant Care
1. Adjust watering and sunlight conditions.
Ensure consistent watering by allowing the top inch of soil to dry out between watering sessions. Place your tomato plants in a location that receives at least 6 to 8 hours of direct sunlight daily. 
This can help mitigate leaf curling and promote healthy growth.
2. Use balanced fertilizers. 
Reduce fertilizer application to half of the recommended dose, and avoid using high-nitrogen fertilizers. Over-fertilization can stress plants and contribute to leaf distortion.

New Growth on Top

New Growth on Top
Image by The Spruce
The Fix: Adjust to Gradual Sunlight Exposure
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If you spot your young tomato plants growing with purple leaves or really dark colors on top, it means they’re reaching out for more sunlight but getting a bit too much. They might end up with some sunburn. 

Each of these likely reasons comes with its matching solution, so you can help your plants regain their vibrant green color.

How to Adjust to Gradual Sunlight Exposure
Slowly introduce plants to higher levels of light.
Gradually introduce your plants to brighter light conditions. This can be achieved by moving them to a location with slightly more light exposure over a few days.

Potential Causes and Fixes

Temperature Stress

Temperature Stress
Image by Notcutts
The Fix: Manage Temperature Exposure
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Tomato plants can be sensitive to temperature fluctuations, particularly when exposed to cold conditions. As temperatures drop, the plant’s metabolic processes slow down.

This causes a halt to nutrient uptake, resulting in the dreaded purple tinge. In some plants, the lack of green colors is a good thing, but not in this case with tomatoes.

How to Manage Temperature Exposure
Provide protection for your plants. 
Use frost cloths, temporary shelters, or plastic covers to establish a protective environment around the plants. Ensure that these protective measures are in place during colder nights to create a warm and sheltered space for the plants to thrive.

Phosphorus Deficiency

Phosphorus Deficiency
Image by DR GREEN
The Fix: Improve Phosphorus Content
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Possible RisksModerate ●●○○○

When soil lacks enough phosphorus, the tomato’s leaves and stems can turn purple. It’s because phosphorus really matters for tomatoes to grow and move energy around. 

When deficient, the plant redirects resources, causing the characteristically unusual discoloration. While the color can look particularly magical, it doesn’t bode well if you don’t do anything about it.

How to Improve Phosphorus Content
1. Add organic fertilizers or compost.
Consider mixing organic fertilizers or compost into the soil. This action assists in restoring a balanced soil composition.
2. Monitor the plants.
Periodically conduct soil tests to assess its health and composition. This practice ensures ongoing maintenance and allows for timely adjustments.
3. Manage pH levels.
Test the soil’s pH and take corrective measures if it’s excessively high or low. Extreme pH levels can interfere with the plants’ ability to utilize phosphorus efficiently.

Root Issues

Root Issues
Image by Greenway Biotech
The Fix: Ensure Good Soil Environment
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Having a strong root system is crucial for plants to absorb nutrients effectively. If the roots don’t grow well due to wrong planting or inconsistent watering, it can lead to leaves turning purple.

When the roots struggle to capture nutrients, the plant’s leaves may signal their distress through color changes. Remember, tomatoes are living things too.

Just like us, they can turn purple when they can’t breathe. Fortunately, you can easily fix this.

How to Ensure Good Soil Environment
1. Pick the right soil.
Go for well-draining soil. This prevents waterlogging and potential root drowning.
2. Water correctly.
Stick to a consistent watering schedule. This helps provide the right amount of moisture without overwatering.
Be cautious not to overwater your plants. This can lead to waterlogged soil and adversely affect root health.
Similarly, avoid letting the soil become excessively dry between watering sessions. This can stress the plants and impede their growth.

Genetic Factors

Genetic Factors
Image by Reddit
The Fix: Provide Proper Care
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Certain tomato varieties tend to end up with purple leaves and stems due to their genetics. Just note that these genetic factors might not always affect how well the plant grows or how many tomatoes it produces.

If you’ve managed to grow that special purple tomato, go ahead and celebrate its unique traits! Personally, we love some healthy purple tomatoes as they make us feel a bit special.

How to Provide Proper Care
1. Care for purple tomatoes as suitable. 
Choose a suitable location for planting that receives ample sunlight. Prepare the soil with compost or organic matter to promote healthy growth.
Plant the purple-tinged tomato seedlings at the appropriate depth, following general tomato planting practices.
2. Provide ongoing care and maintenance.
Keep the soil consistently moist, but not waterlogged. Regular watering is essential, particularly during dry spells.
Apply a balanced, low-cost fertilizer according to the recommended schedule to provide necessary nutrients. Remove any dead or diseased branches to prevent potential risks.

Pests and Diseases

Pests and Diseases
Image by Gardener’s Path
The Fix: Treat and Prevent Pests and Diseases
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Purple discoloration in tomato plants can be caused by pests and diseases as well. Aphids, mites, and specific diseases can easily disturb how nutrients move within the plant. 

This disruption often becomes pretty clear, such as the appearance of purple areas on tomato parts. Plus, these problems don’t just stop with the plants themselves.

Diseases can swiftly spread, and additional insects might easily set up infestations in other plants. It sets off a chain reaction, so you need to stay on top of your game.

How to Treat and Prevent Pests and Diseases
1. Check plants regularly.
Regularly examine your plants for any signs of insects or diseases. Detecting these issues early is crucial for effective intervention.
2. Consider implementing integrated pest management (IPM) strategies.
If you observe insects, consider physically removing them from your plants. This method helps control the pest population without resorting to chemical solutions.
Use natural remedies, such as neem oil or insecticidal soap, to combat pests. These solutions are environmentally friendly and can be effective in keeping pests in check.
Introduce beneficial insects, like ladybugs or predatory mites, to your garden. These insects naturally prey on harmful pests, contributing to pest control in a sustainable manner.

Sunlight Exposure

Sunlight Exposure
Image by Weekand.com
The Fix: Ensure Proper Sunlight Exposure
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EaseLow ●○○○○
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Possible RisksLow ●○○○○

Tomatoes thrive in sunlight, relishing the warmth it provides. However, as the saying goes, too much of a good thing can be a bad thing.

Excessive sunlight, particularly in high temperatures, can induce strain in tomato plants. This stress shows up as a visible purplish hue on leaves and stems.

How to Ensure Proper Sunlight Exposure
Provide shade.
During the sun’s peak intensity, offer a controlled amount of shade to your plants. This can be achieved by using shade cloth, temporary structures, or natural shading elements like nearby trees or tall plants.
The goal is to alleviate stress on the plants caused by excessive sunlight, particularly if you reside in regions with strong sunlight. This shading practice also helps in preventing the occurrence of excessive purpling in the plants’ leaves.

Mineral Imbalance

Mineral Imbalance
Image by Tomato Bible
The Fix: Correct Magnesium Imbalance
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Besides lacking phosphorus, color changes can arise from mineral imbalances. Take magnesium deficiency as an example. 

This can lead to purple veins on a green leaf. By the way, calcium and potassium imbalances can also contribute to color changes.

How to Correct Magnesium Imbalance
1. Do a soil test.
Conduct a soil test to gain comprehensive insights into the nutrient levels in the soil. This assessment will highlight any nutrient excesses or deficiencies present in the soil composition.
2. Adjust fertilizer routine and application.
Modify your fertilizer routine to provide your plants with precise and appropriate amounts of essential nutrients. This tailored approach will address any nutrient imbalances and support optimal plant growth.

Watering Issues

Watering Issues
Image by Tomato Bible
The Fix: Water Appropriately
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EaseLow ●○○○○
Maintenance LevelLow ●○○○○
Estimated CostsLow ●○○○○
Possible RisksLow ●○○○○

Inconsistent ways of watering can stress out tomato plants. When you switch back and forth between letting the soil dry out and keeping it overly wet, it can bother the plant.

This stress can lead to purple discoloration as the plant struggles to manage water uptake and nutrient distribution. Don’t worry too much about it as it’s easily fixable.

How to Water Appropriately
1. Keep a consistent watering schedule.
Water your plants on a regular basis to maintain their health. Consistent watering is essential for their growth and vitality.
Keep a close eye on the soil’s moisture level. Aim for dampness without allowing the soil to become excessively wet, as this can lead to root rot and other issues.
2. Apply mulch to the soil.
Spread a layer of mulch around the base of your plants. This aids in conserving soil moisture, reducing the frequency of watering needed.
Mulch also helps in maintaining a stable soil temperature, which is beneficial for the overall health of your plants.

Chemical Exposure

Chemical Exposure
Image by Minnetonka Orchards

This is also why we usually recommend organic methods to prevent weeds and pests. Organic approaches are gentler and won’t hurt your tomatoes like strong chemicals can.

The Fix: Limit Chemical Exposure
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Certain chemicals, such as herbicides or pesticides, if not used properly or in excessive amounts, can lead to leaf discoloration, including purple hues. Chemical stress can interrupt normal plant processes.

How to Limit Chemical Exposure
1. Use strong chemicals responsibly.
When utilizing chemicals in your garden, diligently follow the prescribed rules and instructions provided on the product labels. 
Prioritize your safety by wearing appropriate protective gear, such as gloves and eye protection, while handling these chemicals.
Apply the chemicals only during the recommended periods. This prevents accidental exposure and helps maintain the health and color of your tomato plants.
2. Immediately perform damage control upon chemical exposure.
If and when plants are exposed to strong chemicals, immediately douse and rinse with water or as recommended by the manufacturer.

Virus Infections

Virus Infections
Image by ibuilder.techinfus.com
The Fix: Treat and Prevent Infections
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Believe it or not, viral infections can sometimes lead to purple streaks or spots on tomato leaves. These infections are usually spread by insects and can cause various symptoms, including discoloration.

Discoloration is the least of your worries when it comes to viral infections. The purple tinge could just be the tip of the iceberg.

How to Treat and Prevent Infections
1. Take action on infected plants.
Regularly inspect your plants for any signs of infection. If you identify any infected plants, take immediate action.
Remove and dispose of the infected plants promptly. This proactive measure significantly hinders the virus from spreading to other plants.
2. Prevent future infections.
Implement insect management techniques, such as using specialized nets or introducing beneficial insects to your garden. These methods contribute to a healthier plant environment and reduce the risk of viral infections.

FAQs on Tomato Plants Turning Purple

Can over-fertilizing cause tomato plants to turn purple?


Yes, over-fertilizing can cause tomato plants to turn purple. Nitrogen-rich fertilizers are often the culprits that lead to purple discoloration in tomato plants. 
Too much nitrogen can mess up the nutrients that plants need to stay healthy. It can make it hard for plants to take in important nutrients like phosphorus and potassium. 
When this happens, leaves and stems might turn purple.

Are there specific tomato varieties more prone to developing purple leaves?


Yes, there are specific tomato varieties more prone to developing purple leaves. Certain heirloom tomato varieties, such as ‘Purple Cherokee’ or ‘Indigo Rose,’ are genetically predisposed to exhibit purple pigmentation. 
The special colors you see happen because of certain pigments in these types. It might be curious, but it doesn’t mean the plant is sick.

Can soil compaction cause tomatoes to turn purple?


Yes, soil compaction can cause tomatoes to turn purple. Soil compaction can restrict root growth and nutrient uptake, potentially leading to purple leaves and stunted growth. 
Hard, packed soil stops water from soaking in and prevents roots from spreading out. This makes it hard for plants to get the nutrients they need. 
To fix this, make sure the soil is airy and loosen it up. This helps get rid of the soil hardness problems.

Could fluctuating pH levels be responsible for purple tomato plants?


Yes, fluctuating pH levels can be responsible for purple tomato plants. This is because pH fluctuations can affect and impact nutrient availability. 
When the soil’s pH gets too acidic or too alkaline, some important plant nutrients are hard for the plant to get. That might make the plant turn purple.
Doing regular soil tests and fixing the pH can help solve this problem and make the plant’s life easier.

Is it possible for purple stems to be a normal part of tomato plant development?


Yes, it’s possible for purple stems to be a normal part of tomato plant development, especially young tomato plants.
This phenomenon is known as “purple stems syndrome”. It’s usually temporary and occurs when plants are exposed to cool temperatures early in their growth. 
But as they grow up and the weather gets better, the purple usually goes away on its own.

Can planting tomatoes in the same location every year cause them to turn purple?


Yes, planting tomatoes in the same location every year can cause them to turn purple. This is due to the depletion of specific nutrients from the soil over time. 
To prevent this, practice crop rotation and enrich the soil with organic matter and balanced fertilizers between planting seasons.

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