Black Aztec is an heirloom corn variety recognized for its mature deep-purple to black kernels. This corn is best enjoyed fresh when it is young and still white.
Black Aztec corn is a warm-season vegetable, meaning it requires warm temperatures to germinate and grow. Plant Black Aztec corn when soil temperatures are at least 55 degrees Fahrenheit after the last frost date. Full sun and well-draining, rich soil are a must for this crop. Black Aztec corn will benefit from a 2-inch layer of compost mixed into the top 6 inches of soil at the planting site. Plant seeds in groups of three spaced every nine to 12 inches along a row. Cover each seed grouping with 1 1/2 inches of soil and water thoroughly. Since this corn variety is open-pollinating, three to four short rows spaced 30 to 36 inches apart allow for adequate pollination.
Although Black Aztec corn is drought tolerant, supplemental watering is important to ensure a healthy, mature crop. It will grow in dry conditions, but cobs will be small with small, hard kernels. Soil moisture is especially critical when plants produce tassels for pollination and during fruit ripening. This corn variety grows best with at least 1 inch of water per week. Water cornrows when rainfall is scarce and when the top 1 inch of soil becomes dry.
Corn plants are heavy nitrogen feeders, and the Black Aztec variety is no exception. Nitrogen deficiencies in Black Aztec corn cause leave to turn yellow and growth to slow. Two high-nitrogen fertilizer applications during the growing season will ensure the crop has sufficient nutrients. Fertilize the corn plants with a 46-0-0 fertilizer when they reach 12 to 15 inches in height. Spread the fertilizer in a line, four to six inches to the side of the plants' bases, at a rate of 1/2 pound per 100 square feet. Rake the fertilizer into the soil and water the ground thoroughly. Make the second application at a rate of 1/4 pound per 100 square feet when plants produce silk tassels.
Black Aztec corn requires minimal maintenance besides watering and fertilizing. Regular weeding around the rows will stop unwanted plants from absorbing nitrogen meant for the corn plants. Removing weeds also eliminates hiding spots for corn pests such as the corn earworm, European corn borer, fall armyworm, or corn rootworm. If these insects become a problem, set traps around the corn plants to attract and catch the insects. This works well for small infestations only. Larger populations must be treated with an insecticide sprayed onto the plant's leaves every five days when the insect's eggs hatch.