Kitchen Scraps That Regrow on a Windowsill

Green onions are the undisputed champion of windowsill regrowing. After using the green tops in cooking, place the white root ends — roughly an inch long — in a small glass with enough water to cover the roots but not the cut end. Set it in a bright spot. Within three to five days, usable green shoots will emerge. A single bunch of store-bought scallions can be harvested multiple times before the roots exhaust themselves, typically over four to six weeks.

Trim from the top and leave at least an inch of regrowth each time so the plant can continue producing. This is one of the few scraps where results are consistently predictable regardless of season or skill level.

Cut the leafy tops from a head of romaine or butter lettuce, leaving the bottom two inches of the base intact. Place the stub cut-side up in a shallow dish with about half an inch of water. Within a week, small new leaves will emerge from the center. These regrown leaves tend to be smaller and slightly more bitter than the original head, but they're perfectly usable in salads or sandwiches.

Replace the water daily — lettuce bases are prone to bacterial rot faster than other scraps. Expect one solid regrow cycle of two to three weeks before the base stops producing reliably. Iceberg lettuce follows a similar pattern but regrows more slowly and with less leaf mass.

Celery works similarly to lettuce: cut the stalks away leaving the bottom two to three inches of the base, then stand it in a shallow dish of water. The inner core begins generating new pale-yellow shoots within a week, which gradually green up with light exposure over two to three weeks. The new stalks won't reach full grocery-store size on a windowsill — they're better treated as a mild celery-flavored herb for soups and stocks than a full vegetable replacement.

For anyone who only uses small amounts of celery regularly, regrowing the base is a genuine money-saver since celery bunches are often partly wasted before they're used up.

Store-bought living basil and mint plants — sold as potted herbs in grocery stores — can be propagated from their stem cuttings rather than discarded. Take a four-to-six-inch cutting just below a leaf node, strip the lower leaves, and place the stem in a glass of water so at least one node is submerged. Roots typically emerge within one to two weeks in a warm, bright spot.

Once roots reach about an inch long, transfer to potting mix for sustained growth. Water-only basil will eventually stagnate without nutrients from soil, so this method is a propagation step rather than a permanent growing arrangement. For a more detailed look at cuttings propagation across other plant types, see our guide to propagating from cuttings.

Lemongrass stalks sold in the produce section often still have a small root nub at the base. Place one or two stalks root-end down in a few inches of water in a tall glass. Change the water every two days and keep it in a warm, sunny spot — lemongrass needs more light than most windowsill regrowers. Thin white roots emerge within one to two weeks, followed by new grass-like shoots from the center of the stalk.

Once actively growing, lemongrass benefits from being moved into a pot with well-draining soil. It grows slowly indoors but can be maintained as a long-term kitchen plant used for tea and Southeast Asian cooking. It's one of the higher-effort scraps on this list but also one of the harder ingredients to find affordable and fresh in many parts of the US.

Several commonly recommended scraps produce disappointing results worth knowing about upfront. Avocado pits take months to sprout, require a specific setup, and produce an ornamental plant — not edible fruit — on a reasonable timeline. Onion and garlic bulbs will sprout green tops in water, but the tops are significantly more bitter than scallions and the bulbs deteriorate rapidly. Ginger can be coaxed to sprout in water, but it does far better started directly in moist soil with warmth and humidity rather than a cold windowsill jar.

Pepper and tomato seeds occasionally germinate in water but need soil and significant light to become productive plants — windowsill regrowing is not the right method for them. For readers interested in growing from seed more broadly, our plant-by-plant guide to low-maintenance edibles covers which crops offer the best return on effort.