In gravelly or thin soil, mature stalks will be tough and stringy. If you're starting with poor soil, work in plenty of well-rotted compost before planting. Sow seed outdoors a week or two before the last expected frost date in your area. As with beets, a Swiss chard seed is actually a dried fruit containing several seeds, so one seed can produce up to five seedlings. After germination, thin plants to one seedling every 4 inches, and thin again when they are about 6 inches tall to about 8 inches apart.
Thinnings are delicious in salads or quickly sauteed.
Once plants are 6 to 8 inches tall, feed with a high-nitrogen organic fertilizer such as soybean, cottonseed, or alfalfa meal. Spread 10 pounds per 100 square feet, or about 1 pound per 10 feet of row, and cultivate it lightly into the soil. As an alternative fertilizer, use fish emulsion at rates recommended on the label. Apply fertilizer when soil is moist but not wet, and ideally just before rain or irrigation. Nitrogen is the key to producing good quantities of tender chard with luxuriant, dark green leaves.