Many gardeners in northern states wait until mid-May or Memorial day to begin planting their vegetable garden. That’s typically when we can expect the last spring frost to occur. But if you wait until then, you’re missing out on many easy-to-grow, frost-tolerant leafy greens. By the time spring rolls around, I’m anxious to plant kale, lettuce, Swiss chard, spinach, beets and bok choy. They’re nutrient-rich edibles that grow well in the spring and again in the fall when the weather is cool.
In our garden, planting cool-season edibles takes place long before late May when I turn to heat-loving tomatoes, peppers and squash. Gardeners often rely on the calendar to decide when to plant. However, I use an inexpensive soil thermometer. That’s because the seeds of leaf lettuce can germinate when the top inch of the soil reaches 41 degrees F. Spinach seeds germinate when the soil reaches 50 degrees. You can find soil thermometers (digital and manual) online and in many garden centers. And while a thermometer is nice to have, once the daytime temperatures reach the 50’s, the soil is usually ready for sowing greens.
Unlike tomatoes and peppers, cool-season greens can be grown in semi-shade and in containers. I sow seeds of Black Simpson leaf lettuce and spinach each spring in a north-facing window box, in pots near the house, and in a recycled wheelbarrow. All of my planters hold soil-less potting mix that provides vermiculite and slow-release fertilizer. A watering can with a gentle spray moistens the top inch or so of the potting mix before the seeds are sprinkled thickly across the top. I pat the tiny seeds in lightly–they should be very near the soil surface. I crumble a fine layer of potting mix just to barely cover them and give them a quick spray of water. In about 6 to 10 days the seeds will sprout. Once the leaves reach four inches or so, I use scissors to harvest several of them for a salad. The lettuce and spinach quickly send up new leaves so you can cut the plants several times before the weather gets warm and the plants are finished.
With so many types of lettuce sold in seed packets, you can grow a variety of leaf shapes and colors. Varieties such as Red Lollo, Red Rosie, Merlot, Firecracker and Dark Lollo Rossa are just a few of the red-tinged lettuces that make a stunning addition to a salad and to your containers.
Swiss chard is another colorful spring favorite that is very easy to grow from seed. You could spend $4 in a produce department for a small bunch of often tough chard leaves that may not be quite fresh. But, the same amount will buy a hefty seed pack that will produce many plants. During spring, I sow about 10 to 15 Swiss chard seeds every few weeks in the ground, in a pot or even in a window box so I have an ongoing harvest of baby leaves. Chard seeds start to germinate as soon as the soil temperature reaches 41 degrees. Although some sources say that Swiss chard prefers cool, mild weather, dozens of our plants provided many meals throughout the summer heat.
One of my favorites, Bright Lights Swiss chard is a multicolored mix with green, red and bronze leaves and stems of many colors–gold, pink, orange, red and white. You can begin harvesting the baby chard leaves as soon as 28 days after the seeds sprout. The tender young leaves may be eaten raw in a salad, they can be simmered or stir-fried, or you can make a nice quiche with them.
Although beets are grown in spring mostly for their roots–those burgundy, golden or striped orbs that can be roasted, steamed or simmered–their leaves when young can be used raw on salads. One of my favorites is the old-fashioned Bull’s Blood beet that produces incredibly deep red leaves that are as ornamental in a pot as they are on a dish. Begin sowing beed seeds when the soil has warmed to about 45 degrees. For a continuous supply of greens and small tender beets, I sow the seeds at 2-week intervals.
Some of the tastiest, nutritious edibles that can be sown in early spring are the Asian greens, such as mustards, Chinese (Napa) cabbage, bok choy and choy sum. Their leaves are often colorful and crinkled, they’re low in calories, high in fiber and they offer plenty of vitamins A, C and K. And, their culinary potential is impressive. They can be stir-fried, steamed, braised or grilled. You can use the small delicate-textured leaves in salad or chop the larger stems and leaves and simmer them in soup.
Most spring greens are very cold tolerant. However, when the temperature dips near freezing, I cover the plants with a lightweight row cloth, available from garden centers. You could also cover them with plant pots or plastic garbage bags that can be slipped over the pot.
Flea beetles, slugs and occasional caterpillars can sometimes pester the leaves. Use floating lightweight row covers or handpick insects. But perhaps more important is keeping the plants watered. As the daylight grows longer and the temperatures rise in June, the leaves often become tough and bitter and the onset of hot, dry weather can finish a crop. For a second fall harvest, sow seeds 30 to 40 days before the first frost, which typically occurs about October 15. Because seeds can be difficult to find in mid-summer, some gardeners buy two packets—one for spring and another for sowing in late July.
Check your local garden centers for seeds along with these mail-order sources.
John Scheepers Kitchen Garden Seeds, 860-567-6086 or www.kitchengardenseeds.com.
Johnny’s Selected Seeds, 207-861-3900 or www.johnnyseeds.com.
Territorial Seed Co., 541-942-9547 or www.territorialseed.com.
Sources for Recipes
Swiss-Chard: A Gardener’s Dream
http://dish.allrecipes.com/swiss-chard-a-gardeners-dream/
Stir-fried Bok Choy with Ginger
http://www.epicurious.com/recipes/food/views/stir-fried-shanghai-bok-choy-with-ginger-231200