Lettuce Turning Red: Causes, Prevention, And Signs Of Spoilage

The more familiar lettuce leaves color is a vibrant green. Sometimes, you find the leaves of your lettuce turning red and it sparks concerns of spoilage or a deficiency in the green. You find this phenomenon in fresh lettuce that you left in the crisper.

First, you should know that lettuce thrives well in cool weather, with the right amount of moisture. Between 45 to 64 degrees is considered the optimal temperature for growing lettuce.

Also, the variety of lettuce you plant, and the time of planting are other factors that influence the growth of lettuce.

That being said, your lettuce could be turning red for several reasons. Most importantly, do not fret. You can still use the leaves in your salad, soups, rolls, and wraps. However, you should know why your lettuce is turning red.

Why is my lettuce turning red?

Here are some reasons your lettuce leaves are turning red:

1. Exposure to ethylene gas

When certain fruits and veggies ripen, they release ethylene gas. Storing lettuce with such fruits and veggies exposes the leaves to ethylene and makes them turn red. Some of these fruits and veggies are bananas, apples, tomatoes, and apples.

2. Exposure to oxygen

Oxygen is not a 100% friend of lettuces. While it helps their growth, prolonged exposure to exposure causes a breakdown of the cell walls, which is seen as the red pigment on the surface of the greens.

3. Oxidation

Oxidation makes greens deteriorate. Varieties like iceberg lettuce are high in iron and they oxidize quickly when exposed to oxygen.

However, it is safe to eat after removing all the red areas. Also, you should use up the lettuce quickly to avoid further spoilage.

4. Damaged plant cells

Damages on the cell walls during harvest can also expose lettuce to oxidation. When the leaves get crushed, air enters the capillaries, and an enzyme triggers the red coloration.

Additionally, other factors such as too little water, too little sunlight, and too much fertilizer can also cause damage to the cell walls.

5. Exposure to high temperatures

High storage temperatures can also make lettuce leaves turn red. This is common with lettuce stored in the refrigerator but not in the crisper.

Frequent opening and closing of the refrigerator door make the temperature fluctuate and cause rusty red spots to appear on the leaves.

6. Handling

Another reason why your lettuce is turning red is because of how you handled it. Cutting it with a rusty knife, harsh handling, tearing, bruising, and trauma stimulates the release of phenols which makes the surface of the leaves turn red.

Can I still eat lettuce that is turning red?

It is safe to eat lettuce leaves that have turned red. You may not like the sight because it looks odd compared to the vibrant green you know, but it is perfectly fine.

If you cannot stand the sight, use a clean sharp knife to remove all the red areas and use the rest of the lettuce head.

As long as you are sure the leaves have not gone bad, you can add them to your salad bowl, soups, and BLT. You can also braise, grill, sauté, or add them to crackers for a midday snack.  

How can you prevent lettuce from turning red?

Lettuce is sensitive to oxygen and humidity. To control humidity, maintain proper airflow in the storage environment. Store lettuce leaves in breathable containers or bags so they release excess water and regulate their moisture content.

The best place to achieve this is the crisp drawer of your refrigerator. When storing lettuces, keep them away from fruits and vegetables that release ethylene gas. Some of these fruits and vegetables are peaches, tomatoes, pears, and apples.

Additionally, minimizing moisture can also help to keep your lettuce from turning red. To keep out excess moisture, wrap them in napkins or cotton cloth, or dry them in a salad spinner and move them into an airtight container.

All these methods work, but you will save yourself a lot of trouble if you buy only as much as you can use within a short time.

Which lettuce varieties are naturally red?

Some lettuce varieties naturally have red leaves. These varieties include:

  • Lollo Rossa
  • Red Romaine Lettuce
  • New Red Fire Lettuce
  • Red Sails Lettuce
  • Redina Lettuce
  • Henry’s Leafy Friend
  • Galactic Lettuce
  • Benito Lettuce

The red leaf lettuce looks a lot like Romaine lettuce, but it is not. The whole leaves or the tips could be red. The red leaf lettuces have loose, soft leaves and are popularly used in some salad dishes.

Red leaf lettuce is the same species as green leaf lettuce but a different cultivar. The color difference is due to the buildup of a natural plant chemical called anthocyanins.

If you have eaten the red leaf lettuce, you will agree that it tastes, just like the green-leaf variety. They have crisp leaves and a mild, sweet flavor. They are also used similarly, but the red leaf lettuce adds more appeal to salad dishes.

Nutritionally, there isn’t so much difference between the two. Both are rich in vitamins and minerals but low in fiber, fat, and protein.

Green leaf lettuce has 0.5 grams of protein and 0.4 grams of fiber against the 0.3 grams of protein and 0.2 grams of fiber in red leaf lettuce.

Furthermore, both varieties are rich in antioxidants, may help lower blood pressure, are good for heart health, and are easy to incorporate into any diet.

How to identify lettuce that has gone bad

To identify lettuce that has gone off, check for the following signs:

  • Mushy, slimy, and darkened leaves
  • Off-putting smell
  • Wilting leaves
  • Mold growth on the leaves, the base, or in the bag
  • Beads of water in the lettuce bag

If the top leaves are mushy, slimy, and have dark spots, peel up to two to three layers to check how far the rot has spread. If no more than two to three layers show these signs, you can use the rest of the lettuce head. Otherwise, trash the entire lettuce head.


Can you eat lettuce with brown spots?

Lettuce with brown spots is not poisonous, and you can eat it if you don’t find its appearance disturbing.

These spots could be a result of high storage temperature. If there are no signs of spoilage, you can cut off the affected areas and use the rest of the lettuce.

What does fungus on lettuce look like?

Fungus on lettuce appears as yellow or brown spots on the upper part of the leaves, fluffy gray mold on the underside of the leaves, and wilting.

How long does it take lettuce to go bad in the refrigerator?

How long lettuce lasts in the refrigerator depends on how you are storing it. Unwashed and uncut lettuce will last up to three weeks in the fridge.

However, the storage period reduces when you wash and shred the greens. Shredded lettuce will last one week in the refrigerator if you keep it in an airtight container or bag.

Can you store lettuce in water?

Yes, you can. Storing lettuce leaves in water in the refrigerator can help keep the greens fresh for up to a month. Wash the leaves clean and submerge them in a bowl of water.

It keeps the leaves fresh and free of mold spores all through the storage period. However, you must change the water every three days to keep the leaves looking vibrant.


Lettuce turning red is not a cause for concern as you thought. The red leaves could be due to excess moisture, ethylene gas absorption, oxidation, damaged cells, or because you cut them with a rusty blade. For all these reasons, it is still safe to eat the lettuce.

If you are so concerned about the redness on your greens, you can tear or cut off the red spots or surfaces and continue with the rest of your lettuce. However, you should take an extra step to examine your greens for any sign of spoilage.

You should also know that some lettuces are naturally red. So, you should also know the variety of lettuce you have.

Another common phenomenon in lettuce leaves is the invasion of bugs. Find out how to control and prevent this.

Thanks for reading.