Why Do Peppers Turn Red?

Though we don’t think about it as we tend to our tomatoes, eat a salad, or slice open a watermelon, our organic vegetable gardens are laboratories of fascinating organic chemistry processes. These processes explain many of the changes we see in plants as the long, warm days of summer give way to the crisp air and earlier sunsets of autumn.

For example, why do peppers start out green and transition to yellow, orange, and red?

Early in a plant’s life, priority is given to growth.  Light is converted into chemical energy via photosynthesis, a process that relies on a green pigment called chlorophyll.  Short days and cold nights signal an end to the growing season and as the chlorophyll breaks down, yellow and orange colors become visible.

Additional chemical changes also contribute to the visible color of peppers.  As the fruit ripens, the concentration of lutein, violaxanthin, beta carotene, capsanthin, and/or capsorubin increase, enriching the yellow, orange, or red color.  As a nice bonus, some of these compounds contribute to ripe peppers sweetness and have been shown to have health benefits.

Many vegetable garden plants become sweeter as the temperature becomes colder, usually as the result of starch being converted to sugars. Why did plants evolve this mechanism? The increased level of sugars means plants cells are less likely to freeze. This conversion is especially common in root crops like carrots or parsnips. Some leafy greens such as kale also produce more sugar as the temperature drops.

So even if you hate the cold and wish summer could last forever, at least you can look forward to even more delicious homegrown garden treats as we head into fall!

Interested in having an organic garden in your backyard? The expert gardeners at Homefront Farmers are here for you and your family. We offer local gardening services to aid in your home’s backyard gardening. Contact Homefront Farmers today for a complimentary site evaluation!