Those one-pound clamshell packages of mixed greens can be a good deal if they're fresh when you buy them. Before you throw them in your cart, make sure to inspect the bottom of the package for signs of spoiling greens; if you can see yellow leaves or, worse, brown rot, don't buy it.
One problem with these packages is that the lettuce is crammed in, hastening the spoilage. And some of the greens in the mix—mizuna and baby spinach, in particular—spoil more quickly than the others, ruining the whole batch for anyone disinclined to spend a lot of time picking out the slimy offenders.
Fortunately, there's a way to extend the life of your salad mix. After you've taken some out to
make a salad, shake up the package to give the remaining leaves some air. If you diligently do this every time you create a little more room, your salad mix will stay fresh for up to two weeks.
Our local grocery is now selling a one-pound package of salad mix for $6.99, which we consider a bargain, compared with the unavoidable waste involved with head lettuce. Sometimes, though, the premixed packages are way overpriced—those five-ounce bags are particularly egregious. At these times, head lettuce is a better deal. If you find run-of-the-mill romaine and red-leaf too boring, you can liven them up by adding arugula and sliced radicchio.