How to Grow Green Beans

Bush, pole or half-runner

Green beans, also called snap beans, are the immature pods of the common bean. Many are actually yellow (wax beans) or purple; University of Maryland Extension points out that “green beans” refers to the unripe pod, not the color.

Bush beans are compact, need no support and are ready in about 50-60 days. They bear for about 2-3 weeks, which allows two to four pickings. Pole beans climb, take about 50-70 days (UF/IFAS) and keep bearing for 5-6 weeks or longer if picked. Utah State estimates 10-12 pounds per 10 feet of row for pole beans against 7-10 pounds for bush beans. Half-runners sit in between, with runners about 3 feet long, and Maryland notes they are usually grown like bush beans, though a trellis can raise their yield.

For varieties, Utah State lists Blue Lake, Greencrop, Gold Crop, Kinghorn Wax, Royal Burgundy, Slenderette, Strike and Tendercrop as bush beans for Utah, and Blue Lake types, Kentucky Wonder and Romano as pole beans. UF/IFAS recommends Bush Blue Lake, Contender, Roma II, Provider and Cherokee Wax (bush) and McCaslan, Kentucky Wonder, Blue Lake and Rattlesnake (pole) for Florida, and advises rust-resistant varieties. In Hawaii, the University of Hawaii bred the pole beans ‘Hawaiian Wonder’ for rust resistance and ‘Manoa Wonder’ and ‘Poamoho’ for root-knot nematode resistance.

Wait for warm soil

Beans are frost-tender, and their seed rots in cold, wet ground. Utah State says germination drops sharply below 60°F soil. The difference is easy to see in UC Cooperative Extension’s germination table: snap beans take about 16 days to emerge at 59°F, 11 days at 68°F and 6-8 days at 77-86°F. A soil thermometer at planting depth settles the question better than the calendar.

Sources differ on how early to push it. Maryland says to wait until frost danger has passed. Utah State allows sowing from about a week before the frost-free date, or 2-3 weeks before it under plastic mulch or fabric row covers. The dates for your zone above show the usual window, and the companion page on when to plant green beans covers succession and fall sowings in detail.

In the hot South and the low desert, beans have two seasons rather than one: late winter to spring and late summer to early fall, skipping midsummer. Frost-free South Florida can sow from September right through April.

Planting

Choose full sun and well-drained soil with plenty of organic matter. UH CTAHR gives pH 6.0-6.8 as the best range. A soil test tells you whether lime or fertilizer is needed.

Recommended depths vary: Maryland ¼-½ inch, Utah State 1 inch, and UF/IFAS and UH CTAHR 1-1½ inches. In heavy clay, pay attention to depth: Utah State notes that a soil crust can keep seedlings from breaking through.

Spacing depends on type. Sow bush beans 2-4 inches apart in rows 18-30 inches apart. Sow pole beans 4-12 inches apart along a trellis, with 24-40 inches between rows. Maryland notes that coating seed with a bean inoculant (nitrogen-fixing bacteria) may raise yields on ground where beans have not grown before, and suggests covering new sowings with row covers if birds pull up the seedlings.

Pole beans need a sturdy support 6-8 feet tall that can stand up to summer storms. Maryland notes that they climb vertical supports but will not weave themselves through horizontal wires, so use poles, tripods, netting or strings. UH CTAHR says most pole varieties start vining 2-3 weeks after emerging, so have the trellis in place by then. UF/IFAS also notes that pole beans can be grown with sweet corn, using the stalks as support.

Water and feeding

Keep the soil evenly moist, especially once flowering starts. Utah State says water needs peak during flowering and pod sizing, and drought then causes dropped flowers, smaller pods and stringy beans. Heat above about 95°F with dry soil does the same. Do not overwater, though: Utah State warns that wet soil promotes root rot and slows growth. A mulch of straw or grass clippings holds moisture and suppresses weeds. Hoe shallowly to protect the roots.

Beans have low fertilizer needs. Utah State says nothing extra is needed if fertilizer and compost were worked in at planting, and Maryland says side-dressing is usually unnecessary. UF/IFAS recommends half the usual vegetable rate. UH CTAHR, writing for Hawaii’s often phosphorus-poor soils, does suggest a second feeding when plants begin to flower. Wherever you are, too much nitrogen delays flowering and gives leafy plants with fewer pods.

Common problems

• Mexican bean beetle: copper beetles with black spots that look like large lady beetles. Look for yellow egg clusters under the leaves and act while plants are small; Utah State notes larger flowering plants tolerate feeding with little loss.
• Bean rust: a fungal disease best prevented by growing rust-resistant varieties (UF/IFAS, UH CTAHR).
• Bacterial blight: water-soaked spots that spread on leaves, stems and pods in damp weather. Water the soil, not the foliage, and let it dry between waterings.
• Root rot and damping off: seedlings darken, wilt and die after planting in cold, wet soil. Wait for 60°F soil.
• Root-knot nematodes: common in warm, sandy soils. Rotate crops and use resistant pole varieties where available.

Utah State notes that moving beans to a new spot each year controls most diseases.

Harvest

Pods are ready about 7-14 days after flowering. Pick when they are full size, firm and crisp, and snap cleanly when bent. Maryland says the seeds inside should be about a quarter of full size and should not make the pod bulge. Pick every few days; regular picking keeps plants flowering.

Use beans soon after picking, or store them in a perforated plastic bag in the refrigerator for up to a week. They freeze well. Maryland suggests trimming, blanching for one minute in boiling water, cooling in ice water and draining well before freezing.