No one likes seeing that slimy, bitter mess in the bottom of their crisper.
Credit: Suzifoo

A decision to buy leafy greens is always made with the most optimistic of intentions. Only, before you know it, it’s a week later and you’re fishing a bag of sad, slimy leaves out of the bottom of your crisper drawer. So much for that salad. Sigh.

Don’t worry, it happens to the best of us. So why do they go bad so quickly?  “Leafy greens contain enzymes that, like every living thing, naturally age,” says Taylor Arnold, Ph.D., registered dietitian and assistant professor in Arizona. But the greens are more delicate than most other veggies—with a thinner, broader structure, so they're more open to attack.  “The larger surface area is an easier target for microorganisms such as bacteria and mold,” Arnold explains.

It’s this one-two punch that makes the delicate greens go bad before you know it.

But with a little bit of planning and the right tools at your disposal, you can extend the shelf life of your salad greens and rid yourself of that food waste guilt (and lost money). The result? A gorgeously delicious fresh and crispy salad you meant to make for Saturday’s dinner (but put off until Tuesday) can still be a reality.

A Few Simple Steps

Whether you buy your greens in bunches or the pre-packaged variety, the first step is always the same: sort through it and get rid of any greens that have gone bad (or are on the brink). As produce matures, it releases ethylene gas, which can speed up the aging process of the surrounding greens, says registered dietitian Amy Shapiro, R.D. Tossing the greens that are wilted, discolored, or slimy prevents them from single-handedly ruining the rest of the bunch.

Also, don’t wash or prep the greens until you’re ready to use them.  This keeps moisture buildup to a minimum.

Steer clear of storing greens in a bag—when lettuces are clumped together and there’s not enough air circulation, the moisture can’t move, creating the ultimate hangout for bacteria, says registered dietitian Keith Ayoob, R.D. Plus, your greens are more susceptible to being bruised or squished by other foods this way.

The best way to protect and prolong the life of your greens is by storing them in a large container lined with damp—not dry, but not sopping—paper towels. “If you wrap the leaves in a totally dry paper towel, the moisture from the leaves will be absorbed more quickly, and the leaves dry out,” says Ayoob. They’ll still be edible, he explains, but will have lost their crispness. A damp paper towel will give your greens the humidity they need to stay crisp, while continuously wicking the excess moisture that causes rotting and mold.

Start by lining the bottom of your container—or the container the greens came in—with damp paper towel and layer your greens on top. Pack them loosely and do your best to keep the leaves from touching too much, as packing them tightly will make them more susceptible to bruising and rotting.

Place another damp paper towel on top of the leaves and continue to use light layers, ending the sequence with paper towel before popping the lid on. The paper towels will soak up the excess moisture, while the container will protect your greens from being exposed to too much air, says Morgan Statt, health and safety investigator for the site Consumer Safety.

Finally, where you store your leafy greens is just as important as how you store them, says Statt. Always keep your greens in your crisper drawer to protect it from any excess moisture that could speed up the wilting process, and in turn, maximize freshness.

Do Periodic Inspections

Each time you hit the fridge for a dose of greens, make a habit of checking to make sure the paper towels are still damp and that any iffy looking greens are disposed of. How often depends on the greens: Tougher stuff like kale, collards, and mustard greens last the longest. “They may not be as tender when raw, but that’s also what makes them longer-lasting,” says Ayoob. “Their tough, fibrous cell walls help prevent water loss.”

Meanwhile, leafy greens that are softer and contain more moisture—spinach, arugula, watercress—are easily damaged and more prone to wilting, says Shapiro.

When In Doubt, Freeze

If you know that you won’t be able to use up the rest of your greens before they expire, try blending them with water (or coconut water) and freezing them in an ice cube tray, says Arnold. You won't be able to make a salad from them, but you'll have tasty cubes you can add to your favorite smoothies.