Growing greens — lettuce, spinach, arugula and other leafy things — in your vegetable garden produces big pay-offs in taste and nutrition for relatively little effort. And, nothing says summer has arrived quite like a trip to the garden to cut lettuce for a salad.
As with any vegetable garden, the first rule is to grow what you like to eat. Like something peppery and spicy? Try arugula. For stir-fries, grow tatsoi and mizuna. Many seed companies offer mixes of greens, so you can grow a variety of colors, leaf shapes and tastes in one bed.
Where to Grow Greens
Greens do best with about 6 hours of sunlight per day, but can get by with less, especially if some of the sun is in the middle of the day. During the heat of the summer, a part-sun location may keep your greens growing longer without bolting (growing bitter and setting seed). You can grow greens in containers and some gardeners like to grow them near the kitchen for easy snipping. If you choose to use containers, they should be at least 6 inches deep. Plant them thickly and then harvest leaves to give the plants room to grow. Whether in containers or a garden bed, the soil should be relatively rich, so add compost or other organic matter, and it should have good drainage. If your soil is clay, add organic matter to lighten it.
Choose a somewhat protected location for your salad bed as greens dry out quickly in heat or wind. You can tuck lettuce or other greens in between other plants or put them under a row cover for protection.
Many seed packages recommend seeding lettuce and other greens directly in the garden. However, lettuce seeds need air temperatures around 70 F to germinate. So, for your first crop of lettuce, plant seeds indoors, using the method described in our first seed-starting post, then move them to the garden after they have germinated. Spinach and arugula may be seeded directly in the garden early in the season. In fact, research done at the organic farm at the University of Minnesota found that spinach planted in late fall and left outside for the winter germinated earlier and produced a crop earlier than seeds planted in the spring. Seeds need to be only lightly covered with soil. Cover the seed bed with row cover to protect the seeds from birds and other marauders.
To keep yourself from being overwhelmed by greens, plant smaller amounts of seed every two or three weeks. You can continue to sow lettuce through August for fall harvest. In fact, some greens, particularly spinach, taste sweeter in the fall compared to spring.
Care and Harvest
Once your greens are planted, the key is to keep them watered. Greens like relatively cool temperatures and moisture. Plan on providing at least an inch of water a week, either through rain or the hose. You can begin to harvest leafy greens when the leaves are 3 to 4 inches long. Plants that grow in heads, such as romaine and butterhead lettuce, can be harvested all at once, but many salad gardeners use the “cut and come again” method of harvest. This involves harvesting leaves as you need them. You cut the leaves (using a scissors, pruner or your fingers) from the outside of the plant. The lettuces grow from the inside, so new leaves will continue to form.
Unless the weather gets very warm and the greens get bitter, you should be able to continue to harvest through much of the summer.
—Mary Lahr Schier
Follow Notes from Northern Gardener throughout January as we offer our series on 31 Days to a Great Northern Vegetable Garden. Tomorrow: Tips for Growing Tomatoes, Part 1.