String beans produce good crops, (often more reliable than runner beans), in a relatively small space, but need warm conditions for a good start. This vegetable is usually eaten as young fresh pods. In drier regions string beans can be used to create a dry crop. String beans are also known as bush, pole, or snap beans.

Cultural Diversity- Available in climbing or dwarf cultivars, with round (pencil) or flat pods. The lilac, purple, and white flowers are decorative: the pods can be striped, violet, or yellow, as well as green. Yellow pods have a more waxy texture and a good flavor. For growing string beans under cover select compact bush cultivars, or if space allows, grow a climbing variety, which may be less prone to disease, as there is a better flow of air around the plants

Ideal Site- String beans need a warm site and soil, sunny and sheltered. This crop can be grown in an unheated greenhouse or hoop house. They can also be grown in containers. No soil treatment is needed on reasonable soil or soil improved with a previous crop. If not prepare the site by adding a medium-fertility soil improver. The ideal soil pH is 6.5 – 7.5.

Seed to Harvest- 7-13 weeks: Dwarf cultivars start earliest. 16-18 weeks for dry beans.

Cultivation- The minimum germination temperature for string beans is 55F (13C). Undercover: To get an early start for plants for dry beans and for early crops, sow in May undercover in deep wooden boxes lined with newspaper or in biodegradable tubes, root trainers, or 3 ½ in (9cm) pots. Harden off before planting outside only after the last frost.

Outside: Sow from early summer when the soil is warm enough or in late June. Warm the soil with cloches or block plants to benefit early sowings. The last sowings, which should be dwarf varieties, may need cloche protection. Sow 2in. (5cm) deep. Expect about a 75% germination- always put a few extra beans in at the end of a row for transplanting into gaps.

 

Spacing- Rows: Dwarf beans 2-3in x 18-24in (5-7cm x 45-60cm), depending on cultivars. Climbing Beans: Grow up teepees or in double rows 24in (60cm) apart, with 5ft (1.5m) between double rows. Sow 2 sees per support, with 4-5in (10-12cm) between supports. Closer spacing is possible in containers but does increase risk of disease.

Block Planting: Dwarf beans: 6-8in (15-20cm). Close planting delays harvesting by about 1 week or so. Undercover: Use wider spacing to lessen the risk of disease.

Plant Care- Use bottle cloches to prevent pests taking the seeds and eating seedlings. Use tall stakes or pole supports for climbing beans. Taller dwarf cultivars may benefit from the support of twigs. Watering as the pods develop increases the yield.

Problems- Mice, Mexican bean beetle, slugs, red spider mite, black bean aphid, halo blight, viruses

Harvesting- Pick bean pods as soon as they are large enough. Check plants at least every other day, as beans develop very quickly and plants can stop producing as soon as a single pod is allowed to mature. Purple and yellow pods are easier to spot than green beans. Do not pick fresh beans from a drying crop, as this will delay the maturity. Leave the pods to dry on the plants until they rattle. Drying can be completed indoors in bad weather. Hang whole plants upside down in a warm dry place until dry. Fresh beans freeze well.

Nutrients- String beans, while quite low in calories (just 43.75 calories in a whole cup), are loaded with enough nutrients. Runner beans are an excellent source of vitamin C, vitamin K and manganese. Plus string beans are very good source of vitamin A (notably through their concentration of carotenoids including beta-carotene), dietary fiber, potassium, folate, and iron. And, string beans are a good source of magnesium, thiamin, riboflavin, copper, calcium, phosphorus, protein, omega-3 fatty acids and niacin.