Lettuce Turning Red: 3 Common Reasons

If you’ve recently harvested some lettuce from your vegetable patch, only to find that its leaves have started to turn red, you may be wondering what the problem is. It’s important to note that some lettuce varieties have red to burgundy leaves. There are also some common issues that cause lettuce to turn red. This article will look at the main reasons for lettuce turning red.

Why is my lettuce turning red?

If your lettuce has started to turn a brick-like shade of red, this indicates a problem such as oxidation, gases, or natural coloring.

Natural coloring

Lettuce Turning Red

Some lettuces are naturally colored red or reddish-green. These varieties tend to have crinkly leaves that grow in a rosette formation. Red leafed types include Red sails, Red fire, and Revolution. These are some of the best salad lettuces with long leaves that are red or purple at the tips.

Red lettuce contains a pigment called anthocyanin that’s naturally present in their leaves. Anthocyanin is an antioxidant with many health benefits and makes the lettuce very nutritious. Eating red lettuce can help your body to combat free radicals.


If your lettuce has started to turn red after it’s been harvested while in storage, it’s likely to have been caused by oxidation. All fruit and vegetables deteriorate over time due to oxidation. This is most obviously seen on a cut apple that starts to turn brown.

During the harvesting of leafy greens, sometimes the cell walls can become damaged, creating an issue of oxidation. This is where the leaves are crushed, causing air to enter the plant’s capillaries. An enzyme is then triggered, which results in a brick red coloration.

To try to prevent this from happening, make sure you cut your lettuce heads away from the base, exposing very little of the root itself. In addition, you should always try to wash your leaves immediately after harvesting. Ensure that they are dry before storing your lettuce in the fridge. If possible, it’s best to harvest your lettuce just before you want to eat it. This will stop the problem from occurring.

Lettuce Turning Red

Ethylene gases

Ethylene gas can also cause lettuce to turn red. This is a natural gas that’s commonly produced by fruits and vegetables as they ripen. Fruits such as tomatoes and pears produce ethylene gas during the ripening process. It’s often recommended that you store hard pears in a paper bag to help them ripen. This works well as the Ethylene gas surrounds the pears causing them to become ripe.

The problem is that if you store lettuce beside a fruit that produces ethylene gas, then it will affect the lettuce. Many people store lettuce in the fried beside tomatoes. As tomatoes are producing ethylene gas, this also affects the lettuce and can cause it to turn red or brown.

How to prevent lettuce from turning red

In order to prevent lettuce from turning red, it’s important to follow these simple tips:

  • Harvest your lettuce by cutting it low down at the stem. If possible, cut just above the soil.
  • Try not to store lettuce beside fruits or vegetables that produce ethylene gas. In particular, tomatoes, apples, melons, and pears will cause the problem.
  • Store your lettuce in a cold fridge at around 34°F.
  • You can also store lettuce in a sealed bag before putting it in the fried. This is particularly useful if you also have tomatoes in the salad draw.

Can you eat red lettuce?

Red lettuce is perfectly safe to eat. The red coloration comes from anthocyanin, a powerful antioxidant found in lettuce and many other vegetables. Lettuce turns red when the oxygen gets into the capillaries of the leaves as they are cut from the plant. This causes oxidation.

In most cases, this has no health implications whatsoever. If the red coloration occurs after you have harvested the lettuce, this is probably due to gas produced by fruits and vegetables. The best way to prevent this from occurring is to make sure that your lettuce isn’t stored between other fruits or vegetables which produce ethylene gas.


Lettuce turning red is generally caused by one of three issues. These are natural coloring, oxidation, or the production of ethylene gas. Ensure that you harvest and store your lettuce correctly. Harvested lettuce should be kept cool enough and shouldn’t be stored with tomatoes as these produce ethylene gas.