Bean: Snap, Lima, and Dry

Introduction

Snap and dry beans (Phaseolus vulgaris and P. coccineus) are popular and relatively easy to grow in New England. Other specialty beans include lima beans (P. lunatus), which are more difficult to grow, edamame soybeans (Glycine max), and fava or broad beans (Vicia faba). All beans should be planted in well-drained soil and as part of a 3-year minimum rotation to avoid soil-borne diseases.

Seed only when soil temperatures have reached 60°F (late May to early June). Optimum seed germination occurs at soil temperatures above 70°F. If precipitation at bloom is low, irrigation can ensure maximum pod set. Temperatures above 90°F or below 50°F cause poor pod set.

Types and Varieties

• Snap beans can have green, purple, or yellow pods, be velvety or waxy, and grow in bush (P. vulgaris) or vine/pole forms (P. vulgaris and P. coccineus). Pods can be oval, round, or flat (Italian types), depending on cultivar. Filet beans are ones that have slender stringless pods that stay small and thin. Good commercial yields for fresh market are 200 bushels or more per acre.
• Dry beans. In recent years, a significant acreage of pea beans and a small but important acreage of light red kidney varieties have been grown in northern New England. Vermont and Maine have a thriving tradition of growing heirloom varieties. For additional information about dry beans, see the Northeast Dry Bean Production Guide from University of Vermont Extension.
• Specialty beans in New England consist primarily of edamame soybean, lima bean, and fava bean. While these are generally of minor importance in most areas in New England, there are nonetheless areas where they are popular. Warm soil is required for soy and lima beans, while fava beans prefer cooler temperatures. Specialty beans need a relatively long time to maturity (75-85 days), reducing the length of the harvest season and restricting production in northern New England. 

Soil Fertility 

Apply lime according to soil test to maintain soil pH at 6.5-6.8.

Apply no more than 80-100 lb/A combined weight of nitrogen (N) and potash through the planter. Because beans are sensitive to salt and ammonia injury, keep fertilizer 2-3" away from the seed.

A 30 lb N/A sidedress at prebloom may extend harvest period of snap beans and increase yields, especially on sandy soils. Machine-harvested snap or dry beans are unlikely to need sidedressing since they are harvested a single time. Less N fertilizer will be needed if legume sod was plowed down or if manure was applied (see Table 1 and Table 7).

Beans can suffer from zinc (Zn) deficiency and boron (B) toxicity. If soil tests report less than 1.0 ppm Zn, then add 10 lbs per acre zinc sulfate to the starter fertilizer. If soils contain more than 0.5 ppm B, then avoid growing beans in this field.

Plant nutrition recommendation according to soil test results for Bean: Snap, Dry, and Lima

Planting

Seeds may be inoculated with the appropriate isolates of Rhizobium to increase N fixation and yields. Purchase fresh inoculum each year, and follow suppliers' guidelines to make sure that you are purchasing the correct strains to inoculate each crop species.

• Bush Snap Beans: Plants should be spaced 1.5-2" apart within rows, with 8-36" between rows. Use the higher plant population under more favorable environments. Sow 75-100 lb of seed/A (approximately 0.5 lb/100 row-feet) depending on seed type and percent germination. Plant seed 1-1.5" deep, depending on soil type and/or soil moisture content. Repeat seeding every 2-3 weeks for a continuous supply.
• Pole Beans: Pole beans need support, which traditionally was done using a four pole cone. At scale, use a trellis of a large mesh nylon material or chicken wire fencing. Removing the plants from the fence is a chore, while nylon mesh is disposable. For the cone method, plant 6-7 seeds around each pole. When using the trellis or fence method, plant seeds 1-2" deep, 6" apart, in rows 4' apart. One pound of seed will plant 240 row-feet or around 150 poles.
• Dry Beans: Plants should be spaced 2-3" apart within rows, with 28-36" between rows. Rate of seeding depends on seed size, percent germination, time of planting, and row spacing (check seed supplier recommendations for each cultivar). Plant 1" deep in moist heavy soils and 2" deep in dry, sandy soils.
• Soybeans: Direct seed 2" apart within rows, with 15-30" between rows at 1" depth.
• Fava Beans: Direct seed as early as possible so plants grow in cool spring temperatures. Space plants 4-6" apart within rows, with 18-36" between rows.
• Lima Beans: Plants should be spaced 4-6" apart within rows, with 18-36" between rows. Use 40-60 lb seed/A (4-6 oz/100 row-feet). Follow dry bean seeding recommendations.

Harvest

• Snap beans for fresh market should be harvested when they reach the desired size. Beans should be harvested when the pod is bright green and fleshy and the seeds are small and green. Pods should snap easily when bent. Large-scale growers should investigate mechanical harvesters. Hand-harvest multiple times or machine-harvest once when the highest percentage of marketable beans are appropriately sized. Harvesting by hand will need to be done several times a week, but avoid working plants when they are wet. Do not harvest wet beans as the storage will be very poor. Optimum storage conditions are 41-45°F at 95-100% relative humidity, but storage life is short. Temperatures of 38°F and lower may cause chilling injury. After >10% weight loss, beans will not be marketable. Avoid storing or shipping beans with ethylene-generating fruits and vegetables. 
• Dry beans require 90-100 days to mature. Harvest when the majority of pods have turned yellow and dry, but before the pods dry to the point of shatter. Mature beans should be so hard that you cannot easily bite into the seed. Harvesting in the morning while there is still dew can minimize loss to shatter. Mechanized harvesting can be done with a puller-cutter, which will uproot or cut the entire plant and lay it on the ground in windrows as the machine moves along the field. Windrows can be combined when beans have dried to 18% moisture. Once shelled, beans should be conditioned at low temperature and dried to a moisture level of 15-16%, then stored in rodent- and insect-proof bins at 35-55ºF.
• Soybeans: For edamame, clip plants at the soil line once pods just begin to lose their color. Pods can be stripped from plants and sold as is, or whole plants can be sold with pods attached after removing leaves. For dry soybeans, see dry bean harvesting recommendations.
• Fava Beans: Harvest beans for fresh eating by hand harvesting pods once they are plump. This may require opening several pods to gauge the size and feel, since fava bean pods are large and bulky.
• Lima Beans: Harvest should take place when 2/3-3/4 of the pods have filled and are yellowing, but before any pods have dried. Other harvest practices are similar to that for dry beans. 

Defoliants/Harvest Aids for Dry Beans

• carfentrazone (Aim EC): PHI 0d, REI 12h, Group 14. Apply 1 to 6.1 fl oz per acre to use as a harvest aid to dry beans at maturity when 80 to 90% of seed pods are yellow or buck skin in color and only 30% of green leaves remain on the plant. Thorough coverage is essential and multiple applications may be needed. For optimum performance use 15 to 30 gallons per acre finished sprayed with a methylated seed oil (MSO) type adjuvant to ensure thorough coverage and retention for harvest aid.
• flumioxazin (Valor SX): PHI 5d, REI 12h, Group 14. Apply when crop is mature and at least 80% of the pods are yellowing and mostly ripe with no more than 40% (bush type beans) or 30% (vine type beans) of the leaves still green in color. To ensure thorough coverage use 15-30 gallons spray solution per acre. Do not apply more than 3 oz/A during a single application and do not apply more than 3 oz/A during a single growing season. Adjuvant required. Crop oil concentrate or methylated seed oil at 2% v/v should be used. A spray grade nitrogen source (either ammonium sulfate at 2-2.5 lb/A or a 28-32% N solution at 1-2 qt/A) may also be added to the spray mixture to enhance desiccation. Can be tank mixed with glyphosate or paraquat to increase control of emerged weeds and aid in harvest.
• paraquat (Gramoxone SL 2.0*): PHI 7d, REI 48h, Group 22. Apply 1.2 to 2 pt/A in 20 gal water with ground equipment or in a minimum of 5 gal water with aerial equipment. Add spreader (nonionic) at 1 qt per 100 gal spray mix. For vining-type beans or bush-type with lush growth, use a single application of the higher rate. May also be applied as a split application. Do not make more than two applications or exceed a total of 2 pts/A. The split application method may improve vine coverage. Apply when the crop is mature and at least 80% of the pods are yellowing and mostly ripe with no more than 40% (bush type) or 30% (vine type) of the leaves still green in color. Do not apply when weather conditions favor spray drift. A drift control agent may be included to reduce spray drift. Do not use on fava beans. May be fatal if swallowed or inhaled. *Restricted use: Applicators must complete an EPA-approved paraquat training )https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training) every 3 years.
• saflufenacil (Sharpen): PHI 2d. Make a single application of 1-2 fl oz/A in a minimum spray volume of 10 gallons/A over the top of dry edible beans that have reached physiological maturity (at least 80% yellow/brown pods, and no more than 30% of leaves still green for vine-type beans/lentils or no more than 40% of leaves still green for bush-type beans). Thorough spray coverage and a methylated seed oil plus ammonium-based adjuvant system (refer to the Additives Section of label for details) are required for optimum desiccation activity. Allow up to 10 days for optimum desiccation effect.