Leafy Greens From Kitchen Scraps: A Covid Project

Romaine lettuce on a windowsill: from stub to leafy greens in only days. Photo: aurooba.com

Here’s a simple project even non-gardeners can undertake: growing fresh leafy greens from kitchen scraps. It’s simple to do and gives you free food (how neat is that?!) Plus, it’s a great project for teaching stir-crazy children (and adults too) about gardening. 

The concept is simple enough. Many vegetables we buy are perfectly capable of regenerating from the base. Usually, that part of the veggie gets tossed into the compost bin, but in this case, we’ll keep it and get it to sprout anew.

Romaine Lettuce: Our Test Plant

Let’s use romaine (cos) lettuce as an example, as it’s fast, easy and very productive. (You could also use head lettuce, but it’s not quite as accommodating.) 

First, cut off and use the leaves as usual, but leave at least 2.5 cm (1 inch) of the base intact. This stub will easily produce fresh, perfectly edible leaves if you give it a chance. 

Water or Soil?

There are two methods for regrowing lettuce from a stub: placing it in water or setting it in soil. Let’s look at both. 

1. Starting lettuce stubs in water is simple enough. Just place the stub in a bowl or glass and pour in about 1 cm (½ inch) of water. Plain tap water is fine. Place at room temperature in front of a sunny window. New leaves will soon start to appear from the center: literally within days. You can harvest these as needed. White roots will sprout from the base as well. To prevent rot, change the water every day or two. Do remove any outer lower leaf bases that start to turn brown.

The problem with growing in water is that the plants soon weaken and the experience is over within three weeks or so. Yes, you do get a second harvest, but a fairly brief one. If you grow the stub in soil, though, it will regrow fully and can last for months.

2. Lettuce stubs in soil. Instead of placing the stub in water, set it in a 10 cm (4 inch) pot of moist potting soil so the lower 1 cm (½ inch) is covered in soil. You still can start the stub in water if you want, but as soon as you see roots appear, pot it up. Again, you need a bright windowsill. Water as needed to keep the soil at least slightly moist at all times. 

Indoors, you can keep lettuce growing for months and harvest it for just as long, but even there, it will eventually peter out (faster in winter than in summer, give the reduced sunlight). However, lettuce will do even better outdoors. You can grow romaine lettuce outdoors all year in mild climates, but, obviously, not in winter in cold ones.

Acclimatize the growing plant to outdoor conditions (expose it to 2 or 3 days in the shade, then 2 or 3 days in partial shade) before planting it out. The air temperature should be above 15?C (60?C); if not, the shock of the temperature change can cause it to go to seed rather than producing new leaves. If you plant it out in early spring or in fall, do so in full sun. In summer, it will do better in partial shade. 

You can harvest this repurposed lettuce by picking the outer leaves of the rosette that forms or cut it back to a stub (yes, a second time!) once it has regrown fully and it will come back again from the stub as long as conditions are acceptable. Eventually your romaine lettuce will go downhill (it is an annual, after all!), but you can often get two extra harvests from it.

Other Veggies to Try

You can do much the same thing with celery, bok choy, cabbage, green onions, leeks, Florence fennel and even lemon grass. Onions and garlic grown this will give tasty greens you can use, but won’t form a new bulb indoors.

You can also resprout carrot tops, but not for a new root (it will produce only feeder roots when grown this way). Instead, use it as a delicious parsleylike leafy green to add to your cooking. Beets and turnips will likewise give greens rather form a new bulbous base if you sprout them from tops.

Try it and see! You may soon be finding yourself gardening as much from kitchen scraps as from seed!