In home vegetable garden popularity contests, green beans rank second only to tomatoes. Green beans are easy to grow, but gardeners do have to take measure to prevent diseases from damaging or destroying their bean crops.
Green Bean Varieties
Pole beans need support, but they are easy to harvest. Bush beans (aka string beans) are easier to grow because they don’t need support, but they are harder to harvest because you have to search for the beans, which hide under the leaves. Many gardeners grow some of both types.
Commonly grown bush bean varieties include Bush Kentucky Wonder and Derby. Among the many varieties of pole beans, Blue Lake, Kentucky Blue, and Kentucky Wonder are popular. Whether bush or pole, you can choose from classic round beans, flat Italian-style beans, and yellow (wax) beans.
As with all vegetable crops, home gardeners should check with their local cooperative extension service to find out the varieties of green beans that grow best in their areas. You can find the extension office nearest you through the U.S. Department of Agriculture website.
Green Bean Planting and Care
Green beans need warm soil to germinate. Unless it’s an usually warm spring there is no sense in sowing until after all danger of frost is past because seeds will not germinate (at best) or rot (at worst) if the soil is too cold. Except in very hot climates, you can plant every two weeks through early August for a continuous supply of beans.
Sow bush beans two-to-four inches apart in rows that are at least eighteen inches apart. If you are growing poles beans in rows sow then four-to-six inches apart in rows thirty inches apart. If you plan to use individual poles or teepees, sow three-to-five seeds in hills thirty inches apart.
Green Bean Diseases
Sadly, green beans are subject to many different diseases, including:
· Root rots create dry, dark, rotted areas on plant roots and lower stems, stunting or killing the plants. Rots can also hit seeds that are sown in soil that is too wet or cold.
· Anthracnose produces black, oval, depressed sores on pods, stems, and the first leaves that emerge from the seeds.
· Mosaic viruses result in stunted, curled, and mottled young leaves, sometimes accompanied by yellowing. Affected pods are distorted with dark and light green (and sometimes bronze) blotches.
· Bacterial blight produces dead spots and blotches, sometimes with a yellow halo (halo blight), on leaves. Water soaked areas appear on pods when the air is very moist; the spots turn brown as they dry.
Green Bean Disease Prevention
You can protect your beans with minimal, if any, use of toxic chemical pesticides by following certain disease prevention practices.
1. Choose varieties that are resistant to the diseases that are common in your area. (Again, your cooperative extension service can give you that information.) Buy your bean seeds only from reputable seed companies because seeds can be infected with blights, anthracnose, or mosaic virus.
2. Have your soil tested and fertilize your beans according to the soil test recommendations. Plants that have the right balance of nutrients are healthier and less vulnerable to diseases. Low fertility causes weak plants. Too much nitrogen, whether from fertilizer or organic sources like manure, yields rapid new growth that is susceptible to disease problems.
3. Don’t plant beans (or close relatives like peas) in the same place in the garden year after year. A three-year rotation helps control certain plant pathogens.
4. One advantage of growing pole beans is that the leaves and fruit are off the ground. Staking reduces the amount of pathogens splashed on the leaves from the ground.
5. Don’t plant beans near gladiolus because glads are susceptible to a mosaic virus that aphids can transmit to your beans. In fact, you can help keep viruses away from your beans by aggressively controlling aphids in your garden.
6. Stay away from your bean plants when their leaves are wet. Bacterial diseases become sticky when they are wet, which means they can attach to your hands, clothes, and tools, and you can carry them from plant to plant.
7. Remove old plants from the garden right after you harvest the beans. Disease pathogens can grow amidst the stems and foliage and infect future plantings.
8. Inspect your bean plants at least twice a week. If you catch diseases early you may be able to prevent their spread by removing and destroying infected plants or plant parts.
Looking for more information about green beans?
Learn more about growing beans and controlling bean diseases with little or no chemical use:
The University of Illinois Extension has all you need to ever know about Beans.
Fight off pests and see defensive tips on Home Garden Disease Controls: Green Beans.
This .pdf file is is great, it’s an Organic Vegetable IPM Guide.