Ethylene is a natural plant hormone released in the form of a gas. It triggers cells to degrade, fruit to turn softer and sweeter, leaves to droop, and seeds or buds to sprout. While some fruits and vegetables are high ethylene producers, others are more sensitive to it.
You can use this knowledge to extend the life of your produce by keeping certain items separate in the fruit bowl or refrigerator drawer. Ethylene is the reason you shouldn't store onions and potatoes together, for example.
Ethylene may also be used when you want to accelerate ripening. This is the principle behind placing unripe fruit inside a paper bag or other closed container, which concentrates the ethylene. Adding another high ethylene fruit, such as a ripe apple or banana, may also speed up the process.
Here's a list you might want to keep handy:
Ethylene producing foods
apples, apricots, avocados, bananas (ripe), blueberries, cantaloupe, cherimoyas, cranberries, figs, green onions, guavas, grapes, honeydew, kiwifruit, mangoes, mangosteen, nectarines, papayas, passion fruit, peaches, pears, persimmons, plums, potatoes, prunes, quince, tomatoes
Ethylene sensitive foods
asparagus, bananas (unripe), blackberries, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, chard, cucumbers, eggplant, endive, garlic, green beans, kale, leafy greens, leeks, lettuce, okra, onions, parsley, peas, peppers, raspberries, spinach, squash, strawberries, sweet potatoes, watercress, watermelon