University of California
UC Master Gardener Program of Sonoma County
A favorite in the summer garden, green beans are also called snap beans and string beans although modern varieties nearly always lack a string-like layer on the underside of pods.
- Choose bush varieties for early maturity with no need for support.
- Choose pole bean varieties for harvests over a long period; provide sturdy trellising 6-8 ft. tall.
- Consider types of pods when selecting a green bean variety—standard round, flat, green, purple, yellow, waxy—each with a slightly different and distinctive flavor.
- Provide support for 3-5 ft. half-runner beans for even heavier crops on upright growth.
- Select among many dozens of varieties, all suitable for growing in Sonoma County. ‘Blue Lake’ and ‘Kentucky Wonder’ are among the most popular; ‘Kentucky Blue’ combines their qualities.
- Attract hummingbirds with red blossoms of fast-growing scarlet runner beans for both food and ornamental value. Their continued blossoming and fruiting may suffer in very hot microclimates.
Planting and Harvesting
- Wait to plant until all danger of frost is past and soil is warm, usually when daytime temperatures are regularly above 70 degrees and soil is above 60 degrees, May-July.
- Follow package directions when sowing seeds for planting depth and spacing in soil amended with compost. Seeds and roots may rot in cool, wet clay soil.
- Expect sprouting in 7-14 days depending on variety and weather; keep soil moist until germination, then evenly moist but never soggy.
- Plant bush types every 2-3 weeks from May to July for a continued harvest throughout summer and early fall.
- Consider trellising pole varieties with a tripod support for ease of harvesting. Use three wooden poles lashed together at the top with 5-6 seeds planted at the base of poles.
- Pick all types of beans frequently, every few days, before pods begin to bulge to sustain continuous and high quality production.
Care and Problems
- Apply 3-4 in. of compost or other organic mulch to soil beds after shoots are 2 in. tall to keep soil cool, retain moisture, and inhibit weeds.
- Maintain even moisture in the root zone, particularly during bloom periods and when beans form. Dry soil toughens beans and invites pests, such as aphids, spider mites, and whiteflies.
- Side dress with organic fertilizer if production slows.
- Watch for yellowing leaves, a sign of overwatering. Whitish stippling of leaf surfaces from spider mites can be controlled by washing leaf surfaces with a soap solution.
- Delay planting to reduce presence of greenish yellow, spotted, cucumber beetles. Handpick when insect populations are low; place spun fiber row covers over young plants or use yellow sticky traps in beds to help control aphids and whiteflies.
- Sonoma County Master Gardener Vegetable Planting Summary.