Black Beans

Black beans are sweet, meaty beans, native to the Americas and often used in South American, Cajun, and Creole recipes. Black beans are delicious, easy to grow, and dried beans can be stored for 2 years before they start losing their flavor.

Black beans (Public Domain)

Black bean plants

Black beans (Phaseolus vulgaris) are legumes. This means they have nodules on and in their roots that allow them to fix atmospheric nitrogen into a form that they and neighboring plants can use. This nitrogen is only available until legumes begin flowering and producing pods. At that point, they keep the nitrogen for themselves.

The large, familiar seeds of black beans split in half, which tells us that they are eudicots. This means that the vascular bundle forms a ring within the stem, plants have a taproot, and flowers generally have petals that appear in multiples of four or five.

Black beans get their black color from flavonoids called anthocyanins. These are the same water-soluble pigments that give purple cauliflower and blueberries their color.

Black bean varieties

Black beans come in both bush and pole varieties. Pole varieties will climb trellises, cattle panels, and other vertical surfaces, and they tend to be indeterminate, which means they will continue producing pods. Bush varieties tend to be determinate and will produce all of their pods within a two-week time frame. Pole beans produce more pods than bush beans, but bush varieties are best if you are planning on doing any canning.

Whichever variety you should, beans should be harvested as soon as they have plumped up. Leaving them on the plant for too long makes them tough.

Bean plants (Kate Russell)

How to grow black beans

Beans are generally planted directly in the soil in spring and early summer. If planted too soon or too late in the season, the seeds will simply rot in the ground. You can start black bean seeds in smaller pots, but they have delicate roots and do not transplant well. You can also grow them in containers. Just keep in mind that bean root systems need 16-24” deep pots to thrive.

​NOTE: As tempting as it may be to use an inexpensive bag of dried black beans from your local grocery store as your seeds, don't do it. Grocery store items are safe to eat. That does not means that they are safe to grow. Many grocery store plants can carry pests and diseases that may take years to be rid of. Instead, invest in certified disease-free seeds and transplants. Your garden is worth it.

Bean seedling

Black beans prefer warm temperatures (above 70°F) and need at least 6 hours of sunlight each day. They prefer loose soil with a pH of 6.0-7.0. Because they can fix atmospheric nitrogen, there is no need to feed bean plants with nitrogen. If a soil test indicates a nutrient deficiency, you can top dress around plants for the best yield.

Seeds should be planted 1-2” deep and 6-8” apart. Water enough to keep the soil moist (but not soggy) until germination occurs. This should take 8-14 days. After that, water deeply every few days, allowing the soil to dry out between waterings. For a continuous harvest of black beans, you can start new seeds every week or two throughout the growing season. This is called succession planting.

Hand-weed around bean plants by cutting weeds off at soil level. This avoids disturbing bean roots while eliminating competition for water, nutrients, and sunlight. This practice also leaves valuable soil microorganisms in place, where they can benefit the bean plants.

Black beans take 80-140 days to mature, depending on environmental conditions and variety.

Black bean pests and diseases

Disease that tend to affect beans include bean rust, curly top, damping off, Fusarium root rot, mosaic viruses, powdery mildew, and white mold. Most of these diseases can be prevented by avoiding overhead watering and allowing the soil to dry out between waterings.

The real battle, when growing any type of bean, is the army of pests that may go after your crop. These pests include aphids, armyworms, bean weevils, corn earworms, cucumber beetles, cutworms, darkling beetles, earwigs, grasshoppers, leafhoppers, leaf miners, loopers, Lycaenid pod borers, Lygus bugs, nematodes, salt marsh caterpillars, seed corn maggots, slugs and snails, spider mites, stink bugs, thrips, whiteflies, and wireworms, but don’t let that stop you from trying your hand at these productive, delicious, easy to store beans. Three-year crop rotations can help prevent or break the disease triangle for many of these problems.

Beans are easy to work with, they improve your soil, and are a satisfying crop to harvest.