It often seems like some form of magic happens in the kitchen: If you shake heavy cream in a jar, it soon becomes butter; if you roast vegetables or citrus, their flavor becomes so much more robust. One simple ingredient can make an entire dish come together instantly, like a pinch of flaky sea salt sprinkled on chocolate or extra-virgin olive oil drizzled over vanilla ice cream (helpful suggestions from Alice Medrich).
But the wonders of the kitchen don’t stop once you’ve finished cooking: Even once you’ve used however many scallions—or carrots or fennel fronds—as you need in a recipe, the others needn’t go in the compost. They can last a long time. A really long time. You just need to regrow them and—here’s another miraculous part—it only takes one week.
Here are four vegetables that only need one week of water and sunshine to regrow to a point where you can use them. You should change the water when it gets cloudy, but otherwise, this method requires barely any effort. Just chop, regrow, repeat:
Reserve about 3 inches of the butt of the lettuce. Place, bottom down, in a a cozy mug or bowl that will allow the lettuce to lean without falling over, will hold enough water to cover the bottom half of the lettuce, and will allow sunlight to reach the lettuce. Fill with water until the bottom half of the lettuce is submerged. Put the container in a sunny window. You should see growth by the next day, and you may even have enough to cook with in one week. What’s more, bok choy and celery can be regrown in a similar fashion.
Chop off the green part of the scallion, using it however you’d like, but leave about an inch of the white bottom intact. Put the stubs in a narrow drinking glass or shot glass so the scallions can lean without falling over. Make sure the container you choose is clear, allowing sunlight to hit the scallion roots. Fill the glass with a bit of water, and place the container in a sunny spot. You should see some exciting growth after a couple of days. One blogger said she bought a bunch of four scallions and has been regrowing and reusing them for two years. Leeks will regrow just as easily as scallions when treated the same way.
Fennel has such a strong taste that you don’t need more than a few snips of fronds from the bulb to add to salads, dressings, and stocks. Therefore, keeping a bulb on-hand in your kitchen windowsill works perfectly. Place the bulb in a mug or bowl that can hold enough water to cover the bottom half of the bulb while still allowing light to hit it. Fill with an inch or so of water. After one week in a sunny spot, green shoots will sprout from the top.
You can reserve the tops of carrots and regrow greens from them. Just chop off the tops of the carrots, leaving about a half-inch to an inch of the top. Place in a shallow container, add water, and put in a sunny spot. After a week, you should see some strong carrot greens. And really, all members of the turnip family (beets, turnips, parsnips) can regrow their greens this way, not just carrots.