What causes tomato plants to be purple?

Tomatoes are one of the most commonly grown vegetables in home gardens all over the world. While they normally come in shades of red, yellow, pink, orange, and even green, it is also possible to find purple colored tomatoes. However, not many people know what causes tomato plants to be purple. In this article, we will explore the reasons why some tomato plants are purple and what you can do to encourage or prevent it from happening.

Genetic Factors

The main reason why some tomato plants turn purple is due to genetics. Just like humans, plants have genes that determine their physical attributes, including color. Some tomato varieties naturally have genes that produce purple pigments in their fruit and leaves, while others do not. Therefore, if you are looking to grow purple tomatoes, you should choose a tomato variety that has purple genes.

However, it is important to note that not all purple-colored tomatoes are created equal. Some may have deeper shades of purple than others, and some may have purple pigments only on the skin while others have them throughout the fruit. Therefore, it's essential to select a tomato variety that produces the kind of purple tomatoes that you desire.

Sunscald

Sunscald is a phenomenon that can occur on tomato plants when they are exposed to too much sunlight. When the leaves and fruits of a tomato plant are exposed to intense sunlight for prolonged periods, the skin of the fruit may develop purple patches. These purple areas are the result of the production of anthocyanin, a pigment that acts as a sunscreen for the plant.

While sunscald can cause some tomato fruits to turn purple, it is not desirable in most cases. Sunscalded fruits may be prone to bruising and rotting, reducing the yield and quality of your tomato crop. To prevent sunscald from happening, you should provide your tomato plants with enough shade, especially during the hottest part of the day. You can do this by covering your tomato plants with shade cloth or by planting them in an area where they will receive partial shade.

Nutrient Deficiency

If your tomato plants are not getting enough nutrients, they may start to show signs of nutrient deficiency. In some cases, nutrient deficiencies can cause the leaves of a tomato plant to turn purple. This is because the plant is not able to produce enough chlorophyll, which is responsible for giving leaves their green color. When the plant lacks chlorophyll, the pigments responsible for other colors manifest themselves, resulting in purple leaves.

The most common nutrient deficiency that causes purple leaves in tomato plants is phosphorus deficiency. If you notice purple leaves on your tomato plants, you should fertilize them with a phosphorus-rich fertilizer. It's also important to ensure that your tomato plants are getting enough water, as water plays a crucial role in the absorption of nutrients.

In conclusion

In summary, there are several reasons why tomato plants may turn purple. Some tomato varieties naturally produce purple pigments, while sunscald and nutrient deficiencies can also cause purple coloration. Understanding the cause of purple coloration in your tomato plants will help you determine the appropriate action to take, whether it's to encourage or prevent it from happening.