Wash, dry thoroughly, then store with something absorbent. Water left sitting on the leaves is what turns a bag of salad to slime in two days, so the drying step matters more than any container.
What to check
Spin or pat the leaves properly dry, then store them in a container with a sheet of kitchen paper, loosely closed, in the fridge.
Avoidrewashing bagged salad labelled washed or ready to eat. It was cleaned under conditions a home kitchen cannot match, and rinsing it in your sink is more likely to add contamination than remove it. Keep it cold and eat it by the date.
Check the boxon a whole head, look at the cut butt end. It oxidizes on a schedule, going white, then pink, then rust, then brown. A rusty-brown core is an old head however good the outer leaves look.
Keep greens away from apples, bananas and tomatoes. Those give off ethylene, and the small rust-colored freckles it causes along the ribs have a name, russet spotting. That is the damage this bullet prevents.
Whole heads last far longer than pre-cut leaves. Every cut surface is somewhere spoilage can start.
Notegreens want damp and cold while berries want dry and cold, because leaves fail by wilting and berries fail by molding. Strawberries are the exception that wants the coldest shelf rather than the crisper.
Common mistaketrusting the date on an opened bag. Bagged salad is packed under a low-oxygen gas flush and that printed date assumes the bag stays sealed. The moment you open it the clock speeds up sharply, so buy the bag size you will actually finish and eat it within a couple of days of opening no matter what the date says.
If they are not perfect: limp lettuce is usually dehydrated rather than spoiled. Fifteen to thirty minutes in cold water, then spun properly dry, and it takes the water back up and re-crisps. Slimy and translucent is different: that is bacterial and it goes in the bin.
Written by the team behind RIPE, a free app that reads a photo of the whole produce pile and rings the ripest ones. Every cue above is one you can check with your own hands, and it all works with no app at all.