Why Do Broccoli Leaves Turn Purple? Unveiling the Causes and Solutions

Broccoli turning purple might not be as rare as you think. It’s a common occurrence caused by various factors such as insufficient sunlight, nutrient deficiencies, temperature changes, or even the choice of a purple broccoli variety. In this article, we delve into the reasons behind broccoli leaves turning purple, explore ways to prevent and fix the issue, and unravel whether purple leaves are safe to eat.

why are my broccoli leaves turning purple?
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Let’s Talk About Anthocyanin: The Thing That Makes Broccoli Plants Turn Purple

Anthocyanins, flavonoid pigments found in purple, red, or black fruits and vegetables, are responsible for the purple discoloration on green broccoli leaves. They also offer numerous health benefits, ranging from anti-microbial and anti-cancer properties to neuroprotective actions. When broccoli is exposed to sunlight or cold temperatures, the amount of anthocyanin increases significantly, resulting in a beautiful purplish hue on the leaves.

thermometer in cold soil
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Not only does this pigment provide health benefits, but it also adds an interesting visual element to dishes featuring broccoli. Whether you’re roasting it with other vegetables or adding it raw to salads, rest assured that your dish will look as good as it tastes.

Reasons for Broccoli Leaves Turning Purple

Broccoli leaves can turn purple due to various environmental factors such as insufficient sunlight, temperature drops, soil nutrient deficiencies, or over-fertilization. Let’s explore each of these factors in detail.

1. Lack of Sunlight

Broccoli plants require at least 6 to 8 hours of direct sunlight per day to thrive and grow. Insufficient sunlight can cause the leaves to develop a purplish hue. Consider planting your broccoli in an area that receives ample sunlight. If natural sunlight is limited, investing in a grow light can be a viable solution.

2. Temperature Drop

While broccoli is a cool-weather crop, it doesn’t appreciate sudden temperature drops or perpetually cold soil. Extremely cold soil inhibits nutrient uptake, causing the plant to release more anthocyanin and resulting in purple leaves. To combat this, plant your broccoli in a sunny, warmish location and apply a deep layer of mulch to keep the soil warmer throughout the year. Additionally, you can use row covers or horticultural fleece during cold spells.

3. Soil Nutrient Deficiency

Soil nutrient deficiency is a common problem among gardeners. When the soil lacks essential nutrients, such as phosphorus, plants display signs of distress. Leaves may become discolored and start turning purple, and overall growth may be stunted. It’s crucial to identify and address nutrient deficiencies in the soil. Conduct a soil test to determine which nutrients are lacking and replenish them using organic matter or fertilizer.

4. Over-Fertilizing

Over-fertilizing with excessive amounts of nitrogen and potassium can hinder phosphorus uptake, resulting in purple leaves. Therefore, it’s essential to fertilize with precision and care. Determine the composition of your soil and the growth stage of your broccoli before applying fertilizers. Opt for natural, organic fertilizers to ensure the health and flavor of your plants.

5. You Chose a Purple Broccoli Variety

If you intentionally chose a purple broccoli variety, there’s no cause for concern. Purple broccoli is loaded with anthocyanins, offering both health benefits and visual appeal. Keep in mind that the heads and sprouts may be purple, but the leaves of a healthy plant should remain green.

growing purple sprouting broccoli with purple leaves
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Preventing Broccoli Leaves from Turning Purple

To prevent your broccoli leaves from turning purple, provide the right growing conditions, monitor temperature fluctuations, test soil nutrients, and avoid over-fertilizing.

1. Provide the Right Growing Conditions

Ensure your broccoli plants receive 6 to 8 hours of sunlight each day, even during cooler weather. Plant them in a sheltered spot away from strong winds and apply a deep layer of mulch to maintain soil moisture and warmth. Choose a location with rich, well-draining soil to give your broccoli the best chance of thriving.

2. Monitor Temperature

Extreme temperature fluctuations can endanger your broccoli plants. If the temperature drops below 40 degrees Fahrenheit (4°C) for an extended period, cover your plants with a floating row cover or horticultural fleece. On hotter days, provide additional shade to prevent damage caused by excessive heat.

3. Test Soil Nutrients

Regularly test your soil for essential nutrients, including phosphorus, nitrogen, potassium, and other minerals. Identifying deficiencies allows you to add the appropriate soil amendments and correct any imbalances.

testing soil for nutrients to stop purple leaves on broccoli
Image Credit: Canva Pro

4. Avoid Over-Fertilizing

Over-fertilizing can disrupt nutrient balance, stunt growth, and reduce yields. Instead of blindly applying fertilizers, use them judiciously at the appropriate growth stages. Focus on maintaining healthy soil by incorporating compost or well-rotted manure.


Q: Is it safe to eat purple broccoli and purple broccoli leaves?

A: Yes, it is perfectly safe to eat purple broccoli and purple broccoli leaves. The purple color is caused by anthocyanin, a harmless and healthful water-soluble pigment that is intensified by sun exposure.

Q: Does purple broccoli taste different than regular broccoli?

A: No, purple broccoli does not taste different than regular broccoli. The color change is due to the presence of anthocyanin, which is safe and healthy to consume and does not affect the flavor.

Remember, by providing the right growing conditions, monitoring temperature, testing soil nutrients, and practicing appropriate fertilization techniques, you can ensure your broccoli plants stay vibrant and free from purple discoloration.

For more exciting insights on gardening and healthy eating, visit BDK Restaurant.

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