Mustard is easy to grow and nutritious to eat. Planted to mature during the cool weather of early spring and late fall, it produces an abundance of large leaves full of calcium, folic acid, iron, vitamin A and vitamin C. You can eat them raw, boiled or sauteed. Blanch and freeze mustard greens to enjoy them all year long.
The best mustard varieties to grow mature quickly and are slow to bolt, or to reach the stage where growth energy is diverted toward the production of flowers and seeds and the leaves become increasingly inedible. The Florida Broadleaf and the Green Wave meet these criteria, harvesting in about 45 days from planting and not bolting until late. Additionally, the Green Wave is tolerant of warmer temperatures. The University of Illinois Extension recommends an additional variety, the Southern Giant Curled, which harvests in 50 days and grows bright-green leaves of a curled and crumpled texture.
Some diseases to which mustard greens are particularly susceptible, like white spot, are caused by fungi that remain viable in the soil from one year to the next. To avoid problems with fungi, don't use seeds saved from a planting that got infected, and don't plant in areas that suffered from infection within the past two years.
In order for the plants to mature while the spring is yet cool, plant three weeks before the last frost is expected. You can sow in containers indoors and transplant seedlings outdoors after the last frost. Plant again three weeks after the first sowing for an additional crop. For a fall harvest, which tends toward higher quality because of the more reliably cool temperatures, plant from midsummer on.
Plant seeds at a depth of 1/3 to 1/2 inch. If you have worked the soil well, you can plant more shallowly--simply lay the seeds on the ground and cover with a sprinkling of soil.
Thin your mustard seedlings to a distance of 3 to 5 inches apart. You can eat the seedlings pulled up at this time. Due to their younger age, they'll be especially tender and sweet to eat raw.