Lettuce with little brown spots?

What you see: Brown dots on your lettuce, especially along the lower parts of the ribs.
What it is: Russet spotting!
Eat or toss: This is mostly an “eat.” The spotting alone is harmless, however it does make the lettuce more vulnerable to rot; any local microbes might have an easier time digging into it. It’s similar to a bruise. You’ll want to eat the lettuce soon, and as an extra precaution (and this is being very cautious) you may want to avoid serving this portion to anyone with a compromised immune system.

So, why is it OK to eat lettuce with “freckles”?

Many types of produce give off invisible vapors of ethylene gas. Ethylene occurs naturally in plants and prompts fruits to soften and sweeten. Generally speaking, it causes aging.

The trouble is that if neighboring produce is exposed to that gas, it can hasten ripening or otherwise impact quality. Lettuce isn’t a fruit so it doesn’t “ripen”, but, like all of us, it does age. Ethylene accelerates the aging process. For lettuce, which generates much less ethylene than many other types of fresh fruits and vegetables, even low concentrations can cause problems. Which brings us to the weird little dots you see on the lettuce pictured above.

The condition is called “russet spotting.” Ethylene basically damages the cells, causing them to leak substances that mix with each other and oxygen, producing the brown color. The stressed lettuce then also “lignifies” cell walls in the damaged area, which essentially toughens some of the cell walls in the affected area. All this adds up to those brown circles and pitted areas.

Fortunately, this is all an “abiotic” process; no harmful microbes required! For most folks, a good rinse of the lettuce will be enough, maybe a trim for aesthetics. However, those spots signal that cells have been weakened, making the affected portion of the lettuce a touch friendlier to any pathogens that happen to be nearby. So proceed with care if you’re preparing food for anyone who is immunocompromised. And prioritize eating this lettuce; the brown spots indicate an accelerated rotting schedule.

Ethylene exposure can happen at home or before the lettuce gets to the supermarket

You can reduce the risk of russet spotting by storing ethylene-releasing produce, like apples, bananas and avocados, away from lettuce. But sometimes the exposure is out of your control. It can happen on the delivery truck if, for example, your lettuce is packed near ethylene gas releasers.

It’s not fair to exclusively blame other foods though: lettuce produces some ethylene itself. Studies have found that iceberg lettuce produces more ethylene after it’s bruised or cut, making it still more susceptible to russet spotting.

Another risk factor, oddly enough, is exhaust. Ethylene doesn’t only come from other types of produce. Gasoline engines and propane-powered forklifts, which you could easily find in a produce warehouse, also release the gas.

Still more risk factors for russet spotting include harvesting lettuce when it’s over mature, excess oxygen exposure, and too-cold or too-warm storage. By and large, however, ethylene is the primary culprit.

While there’s not much you can do to ensure that your lettuce didn’t share air with a propane-powered forklift or carpool with a bunch of bananas, you can arrange your fridge with wide berth between the produce that will release ethylene and the produce that’s most likely to react poorly to the gas. According to Bluapple, a company that makes an ethylene absorber you can use to extend the life of your food, fruits (including veggie fruits like tomato and avocado) tend to emit ethylene; and vegetables, like this lettuce, tend to be especially sensitive to it. On the company’s website you can search for various produce items to learn about how much ethylene they produce and how sensitive they are to it.

Fridges don’t cause spots on lettuce

And, just to cover our bases, the problem is not the fridge itself. Apparently a number of people have blamed their fridges for russet spotting, prompting GE to note that brownish reddish spots are not caused by refrigerator malfunctions.

Use ethylene to your advantage

And, while the gas has an icky consequence for lettuce, you can also use it to your advantage. If you ever want to accelerate ripening, just stash your fruit next to an ethylene emitter. Put a banana and an avocado together in a cotton or paper bag and odds are good that your avocado will soften faster.

Allow us to entertain you.

Updated March 2026