Beans
The main production areas by acreage harvested of snap beans are Wisconsin, New York, Florida, Oregon, and Michigan.
Production in the southern states is shown in Acres harvested of green limas, snap beans and southern peas in the Southern Region (SR).
Soils and Fertilization
Snap beans.Beans are adaptable to a wide range of soil types but will have difficulty emerging in crusted soils. Cover crops or other types of mulch or use of a rotary hoe may be necessary on heavy soils to break the crust. Beans will grow satisfactorily on heavy soils after emergence, however. Uniform emergence is particularly important for bush type beans which will be onceover mechanically harvested. For maximum uniformity of emergence and subsequent maturity, all areas of the field must be well drained and prepared with no crusted, cold or wet areas. Snap beans prefer a well drained soil with a pH of 5.5 to 6.0 but the pH can be as low as 5.0 if Mn or Al are not present in toxic concentrations. Liming to a pH of 6.0 makes fertilizer usage more efficient, however. Beans are sensitive to boron and may experience toxicity problems in fields where boron is naturally high or where it has been added to meet the requirements of cole crops such as cabbage or broccoli.
If little or no nitrogen is available in the field, snap beans will nodulate and form symbiotic associations with N-fixing bacteria in the soil even without artificial inoculation. Modern cultivars require fertilizer nitrogen for best performance, however. Plants fixing their own N often get off to a slower start in cool spring weather and are less uniform in bloom time and subsequent number of days to harvest, however. Inoculating bean seed with N-fixing bacteria has not been shown to increase yields or even provide nitrogen to snap beans. If not the proper strain, the N-fixing bacterium will be ineffective and possibly parasitic.
Fertilization of beans is particularly difficult in sandy soils because the risk of salt injury to snap beans is high. High salt levels cause shriveled or desiccated areas on the foliage which often resemble cold injury. Initially, fertilizer applications are sometimes broadcast, rather than banded, to reduce salt injury, but sidedressings of N at vining and/or bloom are recommended in sandy soils, or where there have been leaching rains.
In soils where zinc is tied up by high pH and phosphate levels, zinc sulfate may be required. Harvesting one ton of snap beans removes 30 to 74 pounds N, 2 to 6 pounds P2O5 and 5 to 6 pounds K2O from the soil. The chart below provides guidelines for fertilization rates and timing based on soil test results.
Manures can be used to supply nutrients for bean production. Experiments in Alabama showed broiler litter with nutrient levels of 2.8 percent N, 1.6 percent P and 2.2 percent K and applied at a rate of 2.1 tons per acre was as effective as commercial fertilizer.
Lima beans. Lima beans prefer a sandy or clay loam soil type with pH of 6.0 to 6.5. Bean nutrient recommendations based on soil tests covers nutrient recommendations based on initial soil fertility and Chapter One gives organic sources of these nutrients.
Southern pea. When soil test results are not available, fertilization rates for southern pea are to broadcast or side band 3 to 4 inches deep, 10 pounds N, 30 to 50 pounds P2O5 and 50 to 60 pounds K20 per acre, 7 to 10 days before planting.
Planting
Snap beans. Spring crop snap beans are planted 3/4 to 1 inch deep either just before or at the beginning of the frost-free period. Fall crop snap beans are planted early enough in the summer for harvest to be completed before the first killing frost. Row spacings for bush beans are 2 inches in the row and 18 to 36 inches between rows. For pole beans, spacing is 4 to 6 inches in the rows and 36 to 48 inches between rows. See the section below on trellising pole beans.
Trellising
Pole beans are grown on trellises consisting of strings or netting attached to an overhead heavy wire suspended between stakes. For production on trellises, stakes should be spaced 15 to 20 inches apart in the row with 5 to 6 feet of the stake above ground.
A 10-to -12 gauge wire should be nailed to the tops of the stakes so it is taut. Another wire or twine is placed 5 to 6 inches above the ground with twine tied from the top to the bottom wire. Trellises should be in place before the beans begin to run. Trellised beans are easy to harvest, less liable to disease and produce more attractive fruit compared to bush beans. Unfortunately, pole beans often command little more in price than bush beans to make up for the additional costs of trellising and hand harvesting.
Planting and Seed Handling Precautions
Bean seeds sometimes fail to germinate properly because they have dried down too much in storage. Such seed are said to be 'hard'. Depending on the cultivar, seed moisture contents should not fall below 7 to 10 percent. This represents relative humidities in storage of 30 to 45 percent for beans kept at 77 degrees F. In some cases, exposing seed to humid conditions for several days before planting will help, but it is better to use properly stored seed.
Bean seed is fragile and bags of seed must be handled carefully, not dropping or compressing seed bags. Cracking of the seed coats leads to leaching of carbohydrates and rotting of the seed after planting. Breaking off either the plummule or a cotyledon results in 'snakeheads' or 'baldheads' with slow growth, increased disease and insect susceptibility and decreased uniformity. Operating a plate type planter at less than 3 mph and plateless types at 4 to 5 mph will help protect seed during planting.
Lima beans. Bush lima beans are planted 2 to 3 inches apart in the row with 36 to 42 inches between rows. Pole limas are planted on trellises, 6 to 8 inches apart in the row and 42 to 60 inches apart between rows.
Southern pea. Southern peas are planted in rows 20 to 42 inches apart 4 to 6 per foot for bush types and 1 to 2 per foot for vine types.
Climatic Requirements
Beans are day-neutral or short day plants. The optimum temperature for seed emergence is 77 degrees F. Germination is slow at 60 degrees F and seeds rot at lower temperatures. Because of the large volume of the seed relative to its surface area, a moist soil is required for germination. Since bean cotyledons must be pushed through the soil to the surface, a crusted or cloddy soil reduces emergence.
The optimum temperature for plant growth is 60 to 70 degrees F with some growth occurring between 50 to 80 degrees F. Snap beans require 1,050 to 1,150 degree days of heat, with a base of 50 degrees F (see Appendix 3 - Calculating Degree Days for a discussion on calculating degree days). Temperatures above 90 degrees F cause fibrous pods and blossom drop. Very rainy conditions during flowering also can cause flowers to drop. Southern peas are usually considered to be more heat and drought tolerant than snap beans.
Irrigation
Like most large-seeded crops, beans require a moist soil for germination. Water availability at pod fill is also critical to ensure high yields. Snap beans have a higher water requirement that either lima beans or southern peas because they have a relatively shallow root system. Irrigating snap beans two times a week, ¸ inch each time, is more effective than 1 inch once a week.
Rotations
Peanuts are a poor rotation crop since they are susceptible to many of the same diseases and insect pests as beans. In west Tennessee, a suggested rotation is beans planted in early April, followed by a crop of greens planted in mid-August. Squash or pumpkins could also be planted as the second crop. Replanting beans in the fall is not recommended because fall bean crops have more problems with insects and diseases, particularly rusts. Fall crop prices are usually lower than those for the spring crop.
Cover Crops
In a Maryland study, beans were found to respond well to cover crops and to require less N fertilizer in some cases. The following cover crops, hairy vetch, hairy vetch plus wheat, Austrian winter pea, Austrian winter pea plus wheat, wheat, and crimson clover, were killed with herbicides. Potassium and phosphorus were incorporated into the cover crop residue based on soil tests. Several nitrogen fertilization levels were also applied as treatments.
Plots with wheat and wheat/legume mixes needed some additional nitrogen for highest yields butbeans following the hairy vetch, Austrian winter pea and crimson clover covers did not respond to additional N. All plots with cover crops had higher yields than those grown without covers, particularly in the drier year of the experiment.
Growth of the snap beans was delayed slightly on cover crop plots, however, probably due to lower soil temperatures. Overall, the investigators concluded that use of legume cover crops or legume/grass mixtures can provide adequate nitrogen fertilizer for the bean crop as well as erosion control and drought protection.