Chard, or leaf beet, is one of the gardener’s best bets for a season-long supply of fresh greens from a single planting. There are several colors of chard—golden yellow, bright scarlet, green, white, and now a five-color rainbow mix—but really only two types. Stem chard, usually known as Swiss chard, has more or less broad stems and large, tough leaves. The stems have a crunchy texture and a mild, clean flavor; they substitute nicely for celery or pac choi where those two vegetables are not grown, Leaf chard, called leaf beet in Europe, has tender leaves, and much smaller stems; its common name is “perpetual spinach,” as it will produce spinach-like leaves over a long period. The leaves of both kinds make a good boiling green, but the leaf chard is better for salad, especially when harvested young.
Chard is a biennial. During the first season it increases in size, and under favorable conditions stores its excess food reserves in a swollen root; then, in the second season, this food reserve is used to produce a central stalk on which flowers, and then seed, are borne. Most gardeners simply plant chard as an annual, of course, buying new seed as needed. The best soil for chard is nearly neutral, has ample organic matter, and is well drained; cold, wet, acid soils won’t grow good chard, and the foliage will show it—the areas between the leaf veins will be pale yellow with a mottled appearance. They love well- prepared raised beds, therefore we put chard in the third part of our four-year rotation, immediately preceding the legumes, which help restore soil nitrogen levels for the replanting of nutrient-hungry leaf crops.
Like beets, the seed of chard is actually a small, withered fruit containing four to eight seeds, so it should be sown sparsely to avoid later thinning. Set the seeds 1/4 to 1/2 inch deep depending on soil type, moisture, and temperature conditions; they should be placed one or two inches apart in rows eight to twelve inches apart, depending on the cultivar and its size (see below). Equidistant bed spacing is eight inches; the two or three seeds sown in each spot can later be thinned to the strongest plant. Leaf chard can also be planted on an eight-inch spacing, but stem chard should have a foot per plant. It transplants well, so can be started 4-6 week before the last frost for setting out 2 weeks before last frost.
The worst pest we have with chard is the spinach leaf miner, the larva of a small fly which lays a mass of small, white, cylindrical eggs on the underside of the leaves in late spring. After hatching, the larvae burrow into the leaves and then chew passages in between the upper and lower surfaces of the leaves, hence their name. Papery gray areas on the leaves are a sure sign of leaf miners, and infested leaves should be removed from the plants and burned to destroy the larvae. In our garden this pest has a relatively short damage cycle, basically from mid-May to mid-June, and if we can protect the plants with a floating row cover that keeps the fly from laying her eggs, the cycle can be broken. An equally easy method is to delay planting until after the active season of these 1/4-inch, two-winged gray flies. As a leaf beet, chard is also attacked by the Brown Marmorated Stink Bug a horrendous pest currently extent in the Eastern US, though it is spreading rapidly.
You can harvest chard at any time. Simply pull the outside leaves from the plant, leaving the center to continue growing. South of USDA Zone 6, it will survive the winter with only minimal protection and provide early greens before running to seed in the late spring.