March is an exciting month as the garden tasks shift from clean-up and other monotonous tasks to planting. Eager to get their hands dirty, many gardeners will grow cool season vegetables such as leafy greens. There is great variety in this category but in terms of nutrition, not all greens are created equal.
Dark leafy greens, such as kale and spinach, have the highest nutritional value. Beet greens, mustard and collards are other options for the spring, salad mix garden. Less commonly considered, but still healthy and readily available are dandelion greens. Dandelion greens have a strong and tangy flavor which can be a nice accent, when used in moderation. This variety of leafy greens will provide a salad rich in fiber, calcium and vitamins A, C and K.
Direct-seed leafy greens when the soil reaches at least 45 degrees. Soil that is too cold will prevent germination of seeds and may stunt growth of transplants. The soil should be fertile with plenty of organic matter. For the fast-growing, shallow-rooted leafy greens, regular water is necessary but avoid over and underwatering. With insufficient water, plants will bolt which causes the leaves to be tough with a bitter flavor. To maintain soil temperature and moisture level, use mulch around the plants. A soil thermometer is a useful tool at this time of year.
Though leafy greens can tolerate cold air temperatures, freezing temps may cause damage or death. A cold frame or row covers can be an easy solution if a spring freeze is forecast. Create a series of arched frames using one-half-inch flexible pipe. Cut lengths of the pipe so you can create arches that are tall enough to go over the tallest plants to be protected. Attach the ends of the pipe to small blocks of two-by-four-inch sections of wood to hold the arch shape upright when set on the ground. Space the arches apart about 4 to 5 feet. Drape frost cloth, sheets or other protective barrier over the arches on days when there is threat of a freeze. Remove the cover on sunny days.
Spinach and leafy lettuce varieties can be harvested multiple times throughout the season. Remove the older leaves but allow the young leaves to remain intact with the plant and continue to mature until a later harvest. Harvest dandelion leaves while they are young and still tender.
Leafy greens can be at risk for contamination especially if overhead water is used due to contact with the soil. To prevent illness, it is important to thoroughly wash the leaves prior to consumption. Soak the leaves in a bowl of water to loosen soil particles. Then rinse the leaves and pat dry or spin in a salad spinner.
The time is right to direct seed your cool season, spring garden. Choosing a variety of dark leafy greens makes the resulting salad tastier, more visually appealing and provides a wider range of nutritional benefits.
Cynthia Domenghini is an instructor and coordinator for K-State’s horticultural therapy online certificate program.