How long your lettuce stays fresh depends on whether it's iceberg, romaine, a spring mix or one of scores of other lettuce varieties available. That said, if you take time and care with any lettuce once you get it in your kitchen, you can extend its condition and its shelf life.
Choose the freshest lettuce at the store by examining boxed lettuce or lettuce bunches carefully. Look for crisp green leaves with no yellowing or droopiness and no bruises on the lettuce ribs.
Boxed or Bagged Lettuce
For lettuce that comes already washed in plastic boxes or bags, proper storage is the key to freshness:
- Place the lettuce packages in your refrigerator's vegetable bin. Even 1 day on the lowest, coldest refrigerator shelf or 1 hour left out of the fridge damages tender leaves.
- For commercially bagged lettuce or bags of fresh lettuce, experiment with a trick proposed by Dorie Greenspan, author of 10 cookbooks including Around My French Table. Greenspan recommends blowing air into the bag -- the carbon dioxide in your breath offsets oxidation that ages your lettuce.
No matter the inherent shelf life of different lettuce types, proper storage techniques work for all lettuce:
- Avoid washing or tearing lettuce before storing it. Water increases the chances of bacterial growth and the torn leaves provide an opportunity for bacteria to enter into the cell walls of the lettuce.
- Place a few sheets of paper towel around whole heads of lettuce and along the sides and bottoms of cut lettuce. The paper towels reduce condensation and absorb excess moisture.
- Keep all lettuce in an airtight container, such as a plastic bag, to reduce oxidation.
- Make sure that your refrigerator is set to at least as low as 40 degrees Fahrenheit, the temperature recommended by the Foodsafety.gov website.
Expect hearty, thick-leafed lettuce like romaine, iceberg or red-leaf to stay fresh for up to 7 days. Thin-leafed lettuce varieties, such as Boston, butterhead, bibb or a spring mix, stay fresh for 3 to 4 days.
Salads in Your Lunchbox
If you've gone to the trouble of packing a fresh salad for lunch at work or school, the last thing you want is to face wilted lettuce when you're ready to eat. Solve that problem with these solutions:
- Carry the lettuce, the salad dressing and additional ingredients, such as chickpeas, bacon bits, cheese or tomatoes, in separate containers and mix them right before eating.
- Use an insulated bag or box when transporting your salad. Cool temperatures slow the rate of moisture loss and bacterial growth in the lettuce.
- Place the lettuce in an airtight container, such as a glass jar or bowl with a lid, a plastic bag or a hard-plastic container. Your goal is to reduce oxygen, which will dry out the lettuce.
- Place your salad in a refrigerator as soon as you can once you arrive at your lunch spot. If that's not possible, place it out of direct sunlight in the coolest area of the room.