Adzuki beans, also known as azuki (Japan) and adanka beans, are not common in Florida gardens. The crop originated in Japan, where it is an important pulse (dry bean) crop, and in China, where it is very popular. Consider growing adzuki beans in a home garden since the beans are expensive to purchase.
The seeds are used primarily as a dry bean or for sprouts, and are used whole or ground into bean meal, but many cooks use them green. Since they have a sweeter taste than most beans, they are sometimes used in desserts.
The plant is erect, 1 to 2 feet high, although some gardeners have reported them to be indeterminate, growing and producing until frost. The yellow flowers are followed by a cluster of several smooth, short, small, cylindrical pods. Leaves resemble those of Southern peas, while the pods are much like mung bean pods.
The seeds are smaller than common beans but are two to three times larger than mung beans. They are variously colored but most often dark red. Types with green, straw-colored, black-orange, and mottled seeds are known. The round seeds have a hilum (seed scar) with a protruding ridge on the side.
Adzuki beans need about 120 days from sowing to the time the seeds and pods are dry. They need cool nights for best production, but will not tolerate frosts and freezes. They should be planted in Florida gardens during traditional frost-free periods.
In South Florida, September through February is the best planting period, February through March in the rest of the state. When planted in September in North Florida, vigorous plants with 20 to 30 pods were obtained by mid-November.
Prepare the soil and plant very much as for green snap beans. Sow seeds ¾ to 1 inch deep, thinning the plants to stand about 2 to 3 inches apart in the row. Space rows 12 to 18 inches apart. Give ordinary care (no trellis is needed). Adzuki is said to be fairly drought resistant, although the soil moisture should be maintained at a consistent level.
The young, tender pods may be harvested for use as snap beans. However, they are very small at this stage and the seeds are just beginning to develop inside the pods. Pick every 5 or 6 days.
Adzuki beans are most useful as a dry bean. The ripe seeds contain 25% protein and are highly nutritious. The dry pods split open and scatter the seeds, so harvest the pods after the seeds are ripe but before they shatter. The entire plant with dry pods still attached may be pulled and stacked in a dry, well-ventilated place to dry completely (a week or two after harvest is usually sufficient). The dry shelled beans should be stored in a tightly sealed jar in the refrigerator.
Sprouts from adzuki beans are particularly nutty and tasty. Sprout as you would other beans such as mung and soy. Dried adzuki beans are said to require only a short soaking (1 hour) before cooking.