Phaseolus vulgaris
Last revised January 11, 2010.
Photo credit: Bill Mansour, Oregon State University
VARIETIES (snapbeans require approximately 60-75 days to harvest, depending on season, planting date and variety).
Fresh Market
Western Oregon, Bush types for hand picking: Oregon Trail, OSU 91-G (for machine harvest or hand picking). For trial: Fandango, Florence, Impact, Jade, Nickel, Pix, Soliel.
Eastern Oregon, Bush types: Endurance is curly top-resistant. Bush Blue Lake 274, Jade, and Landmark, though not resistant to curly top, do well in most years.
Small-sieve (French types): Minuette, 76-110, Dandy (the latter has lighter green pods).
Italian type: Roma II.
Pole types: Kentucky Blue and FM-1K (Blue Lake types), Cascade Giant (Oregon Giant type, except it is round-podded instead of flat-podded).
Bush yellow pod: Puregold, Sunrae. For trial: Goldmine, Unidor
Bush Romano types: Roma II, Romano FM 14.
Bush yellow Romano: Wax Romano 264.
SOILS
Beans are sensitive to compaction. Avoid excessive tillage and where possible, choose silt-loam fields with good soil structure and internal drainage. Sandy loams are satisfactory but require more frequent irrigation. Avoid soils that crust badly and those with high salt content. Beans produce best on soils which are neutral or slightly acidic. Lime should be applied if pH levels are below 5.8. Follow soil test recommendations.
ROTATIONS
Plant beans in fields that had been in wheat or other cereal crops to reduce damage from soil-borne diseases. Avoid fields containing residues of lettuce, carrots, cabbage, parsnips, potatoes, tomatoes, and cucurbits such as pumpkins, squash and zucchini, since these may harbor white mold disease sclerotia. Also avoid fields which were in strawberries since these may harbor gray mold disease sclerotia.
SEED TREATMENT
Use fungicide and insecticide-treated seed. Processors may have recommendations specific to their needs. Consult with individual companies.
SOIL TEMPERATURE
Good germination is obtained at soil temperatures of 60 F to 84 F. Seed rot is a serious problem at lower temperatures, and seedling injury from soil incorporated herbicides may be increased due to longer exposure times from slow germination. Beans are sensitive to cold water imbibition which may result from early spring rains and cold soils coupled with excessively dry seed (below 10% moisture). This problem may be reduced by conditioning such seed for several days by exposing it to ambient humidity, allowing the seed to absorb moisture from the air. This may be done by opening seed bags and holding them for several days in an unheated barn or storage area.
SEEDING
In western Oregon, green beans are planted from about the end of April to the end of June. Planting of wax beans and Romano beans starts a week later and ends a week earlier. In eastern Oregon, beans are planted from about the first of May to about mid June. The small number of acres grown in eastern Oregon allows planting to be limited to the optimum period.
Some fresh market growers have obtained increased stands and earlier maturity by using crop covers for very early plantings.
Green and wax beans number approximately 100-125 per ounce. Seed size varies by variety and seed lot. In general, large seeds perform better, but are more susceptible to mechanical damage in handling and planting.
Plant at a uniform depth of 3/4 to l.5 inches. Use shallow depths with early planting dates when soils are cold and wet. Plant deeper when soil surface is dry and soils are warm. Make every effort to establish the stand without post-plant irrigation. Plant into moisture or, if soil moisture is too deep, pre-irrigate the field before planting or culti-pack the field lightly after planting to bring soil moisture to the seed level. Irrigation after planting increases the risk of soil crusting, chilling of the seed and unemerged seedlings, and increases risk of anaerobic conditions, and should be done only as a last resort.
Seedlings should emerge in about 10-14 days. Any delay in emergence exposes seedlings to increasing rates of incorporated herbicides, as well as seed and seedling pathogens. Uniform emergence is important, especially at high plant populations, in which a delay of emergence of only 2-3 days behind the rest of the stand will result in such plants being barren.
Always handle bean seed with care. Rough handling lowers the percentage of germination and increases numbers of crippled seedlings. A number of excellent planters are available. The new generation of vacuum planters such as the John Deere Max-Emerge, Monosem, Stanhay, and Gaspardo vacuum units place individual seeds accurately with minimum damage.
SPACINGS
Extensive research at Oregon State University with a large number of green snap bean varieties and advanced O.S.U. breeding lines indicates that 36 square inches/plant (174,000 plants/acre) is optimum for yield. Furthermore, with the same number of days from seeding to harvest, a higher grade (smaller sieve bean) is obtained, resulting in higher quality and dollar value than would be obtained at the more conventional spacings of 45-60 square inches per plant.
Growers use seeding rates of 8 to l2 seeds per foot in rows l5 to 30 inches apart, as required to fit available cultivating, spraying and harvesting equipment. Although close spacings have been thought to increase probability of infections from gray and white mold, experience with close row spacings and high plant populations since the 1970s suggests that this might not be the case, especially when close spacings are coupled with increasing the distance between plants in the row and the availability of effective fungicides.
Increasing the plant population per acre tends to reduce the number of beans per plant but increases the total number of pods (yield) per acre. This also results in pods being borne closer to the stem and higher in the plant canopy, and plants being more upright. When these factors are coupled with increased distance between plants in the row, they tend to compensate for the reduced distance between rows and the potential reduced air drainage. This seems to result in such plantings being no more susceptible (and no more resistant) to gray and white mold than conventionally spaced beans under normal conditions.
Aim for a final plant stand of l20,000-l75,000 plants per acre (depending on spacing between rows). This is usually 75 to 110 lb seed/acre depending upon seed size and germination percentage. Use the higher seeding rates with reduced spacing between rows.
At any given plant population, reducing spacing between rows allows increased distance between plants in the row (example: 5 plants per lineal foot at 15-inch spacing between rows provides the same population per acre as 10 plants per foot at 30 inches between rows). Appropriate spacings between rows at the higher plant populations would be 12-20 inches. Spacings under 12 inches between rows are difficult to accomplish with current planters.
Because of their large leaves and viney habit, bush Romano types should be planted at lower populations of 90,000-100,000 to reduce problems from mold.
FERTILIZER
For the most current advice, see Nutrient Management for Sustainable Vegetable Cropping Systems in Western Oregon, available as a free download from the OSU Extension Catalog
In the production of vegetable crops, good fertilizer usage is only one of the important management practices, including proper seeding, pest control, adequate irrigation, and timely harvest. Because of the influence of soil type, climatic conditions, and other cultural practices, crop response from fertilizer may not always be accurately predicted. Soil test results, field experience, and knowledge of specific crop requirements help determine the nutrients needed and the rate of application.
Fertilizer applications for beans should insure adequate levels of all nutrients. Optimum fertilization is intended to result in top quality and yield, commensurate with maximum returns. Recommendations are based on a row spacing of 30 inches. With decreased row spacings, fertilizer rates should be increased proportionately. Use the following recommended guidelines:
For Western Oregon:
Nitrogen (N)
Rates of 50 to 80 lb N/A are generally recommended where beans are grown on fields having a history of heavy fertilization and intensive culture. Rates of 80 to 110 lb N/A are recommended where forage legumes or heavily fertilized vegetable crops were not grown the preceding year. More N may result in viney growth, delayed maturity, and reduced pod set.
N plus potash (K2O) applications should not exceed 90 lb/A when between-row spacings are 36 inches, or 108 lb/acre for 30-inch spacing. There is danger of seedling injury from the concentration of salt when fertilizer in excess of the above rates is banded at planting time, also:
There is less danger if the row application is split into two bands. The danger is aggravated as the band comes closer to the seed. The danger is greater with sandy than with finer textured soil. Immediate irrigation at the first sign of burn should reduce further injury. There is more possibility of damage to seedlings on acid soils where the pH is below 5.5.
Phosphorus (P)
Phosphorus fertilizer should be banded at planting for vigorous early seedling growth. Bands should be located 2 to 3 inches to the side and 2 to 3 inches below the seed.
Response is greatest from bands properly placed at 2 x 2 inches.
|
If the soil test* for P reads (ppm): |
Apply this amount of phosphate (P2O5) lb/A: |
|---|---|
| 0 - 15 | 120 - 150 |
| 15 - 60 | 90 - 120 |
| Over 60 | 60 - 90 |
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science.
Potassium (K)
Potassium should be applied before planting or banded at planting time. Amounts above 60 lb K2O per acre should be broadcast and worked into the seed bed. See statements on fertilizer banding under "Nitrogen."
| If the soil test* for K reads (ppm): | Apply this amount of potassium (K2O)(lb/A) |
|---|---|
| 0 - 75 | 90 - 120 |
| 75 - 150 | 60 - 90 |
| 150 - 200 | 40 - 60 |
| Over 200 | None |
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science.
In Western Oregon, avoid using chloride forms of potassium in the fertilizer band. There is some research evidence that indicates that these forms may increase manganese solubility and cause manganese toxicity.
Sulfur (S)
Include 20-30 lb S/A in the fertilizer program for bush beans. Sulfur is sometimes contained in fertilizers used to supply other nutrients such as N, P, and K, but may not be present in sufficient quantity.
Plants absorb S in the form of sulfate. Fertilizer materials supply S in the form of sulfate and elemental S. Elemental S must convert to sulfate in the soil before the S becomes available to plants. The conversion of elemental S to sulfate is usually rapid for fine ground (less than 40 mesh) material in warm moist soil.
S in the sulfate form can be applied at planting time. Some S fertilizer materials such as elemental S and ammonium sulfate have an acidifying effect on soil.
The S requirements of Bush beans can be provided by:
The application of 20-30 lb S/A in the form of sulfate at or before seeding.
Applying 30-40 lb S/A as fine ground (finer than 40 mesh) elemental S the preceding year.
Applying coarser ground elemental S at higher rates and less frequently.
Magnesium (Mg)
When the soil test value is below 1.5 meq Mg/100g of soil or when calcium (Ca) is ten times more than the Mg, apply 10 to 15 lb Mg/A banded at planting. If deficiency symptoms appear, spray with 10 lb Epsom salts in 100 gal water/A.
Mg can also be supplied in dolomite, which is a liming material and reduces soil acidity to about the same degree as ground limestone. Dolomite should be mixed into the seed bed several weeks in advance of seeding.
Boron (B)
Responses of bush beans to B applications have not been observed in experiments on growers' fields in western Oregon. Fields which have received recent heavy B applications should be soil tested for B. If the soil test indicates 2.0 ppm B or above, there is danger of injury to beans.
Zinc (Zn)
The application of Zn has increased the yields of bush beans in the Stayton area especially on the gravelly, dark colored soils.
| If the soil test* for Zn reads (ppm): | Apply this amount of Zn (lb/A): |
|---|---|
| Less than 1 | 3-4 banded or 10 broadcast |
| Over 1 | None |
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science.
When the soil test is below 1 ppm Zn, a response to Zn is expected on all soils. When the soil test is between 1 and 1.5 ppm Zn, a response to Zn is expected on most soils in the Stayton area.
Where Zn is required, either 10 lb Zn/A should be broadcast and worked into the soil prior to planting or 3 to 4 lb Zn/A should be banded with the fertilizer at planting time. A broadcast application of 10 lb Zn/A should supply Zn needs for 2 or 3 years.
Lime
Lime applications should be made when the soil pH is 5.8 or below, or when calcium (Ca) levels are below 5 meq Ca/100g of soil.
Possible seedling injury from the band application of fertilizer is less when the soil pH is 5.5 or above. Some Willamette Valley experiments with beans have shown decreased uptake of phosphorus from band applications of phosphorus when the pH approaches 5.0.
| If the SMP Buffer* test for lime reads: | Apply this amount of lime (T/A): |
|---|---|
| Below 5.2 | 4 - 5 |
| 5.2 - 5.6 | 3 - 4 |
| 5.6 - 5.9 | 2 - 3 |
| 5.9 - 6.2 | 1 - 2 |
| Over 6.2 | None |
*Assumes extraction procedures similar to those used by the OSU Central Analytical Laboratory. Specific information on soil test procedures is available from the Dept. of Crop and Soil Science.
The liming rate is based on 100-score lime. Lime should be mixed into the seed bed at least several weeks before seeding. A lime application is effective over several years. Do not apply lime when the soil pH is above 6.0. Yields were reduced in Willamette Valley experiments when lime raised the soil pH to 6.5.
Phosphorus, K, Mg, Zn, B, and lime recommendations are based on soil test values from extraction procedures developed by the Dept. of Crop and Soil Science, OSU, Corvallis, Oregon.
This guide is largely based on the results of experiments conducted by Horticulture and Crop and Soil Science Department researchers of the OSU Agricultural Experiment Station, and is quoted from OSU Fertilizer Guide FG28.
Eastern Oregon, east of the Cascades:
| lb per acre | |
|---|---|
| Nitrogen (N): | 50- 80 |
| Phosphorus (P2O5): | 50-100 |
| Potassium (K2O): | up to 50 |
| Sulfur (S): | 20- 30 |
IRRIGATION
Irrigation is not usually recommended until about 2 weeks after planting (see comments in the section on "SEEDING", above). Too much water at seeding slows growth and may increase root rots. Several light irrigations may be necessary to alleviate a crusting condition.
During the rest of the season, keep moisture levels in the top foot of soil at or above 50% of available water. The two critical periods for water stress during bean development are bloom and pod set. It is advisable to irrigate in the early morning hours so the plants may dry off before the night.
A total of 10-16 inches may be needed in western Oregon depending on location planting date, seasonal variation and variety. Approximate irrigation needs for the Hermiston area have been found to be: 3.5 inches in May, 5.0 in June, 7.5 in July, and 7.0 in August. Irrigation requirements in the Milton-Freewater area are less than for the Hermiston area.
Hand-moved and side-roll systems are most common. Automated lateral-moved tower systems and continuous-move big gun systems are also used effectively. Increased use of large center pivot systems (those covering over 40 acres), in the Willamette Valley may be contributing to production problems with beans. This is especially so with low pressure systems. Problems are caused by water application rates along the outer portions of the circles that exceed soil infiltration rates. This causes surface ponding and increased risk from soil erosion. Also, prolonged periods of soil wetness resulting from necessary frequent water applications, increases the probability of soil compaction from cultivation or other mechanical operations when the soil is wet. Systems larger than 40 acres should be restricted to soils with appropriate infiltration rates (generally 0.5 inches per hour or more). Such soils are not common in western Oregon.
Soil type does not affect the amount of total water needed, but does dictate frequency of water application. Lighter soils need more frequent water applications, but less water applied per application.
Snapbean Water Use:
The following crop water use and irrigation management information is from the OSU Green Bean Irrigation Guide developed by M. Hess, J. Smesrud, and John Selker (Dept. of Bioresource Engineering) and N.S. Mansour:
| Total Seasonal Evapotranspiration (inches) | 10.6 |
| Peak Evapotranspiration Rate (inches/day) | 0.20 |
| Maximum Allowable Depletion (percent) | 50 |
| Critical Moisture Deficit Period: | flowering |
Moisture management in snapbeans is extremely important at all stages of plant development due to its influence on stand establishment, fungal problems, and pod set and quality. Because emerging bean plants can be stressed and damaged when breaking through surface crusts, we recommend that fields be irrigated to field capacity in the top 12 inches of soil before seeding and not again until after emergence whenever possible to minimize surface disturbance. In the remainder of the season, available soil moisture should not be depleted by more than 50 percent1. Also, on fields where root rot has been a problem, beans may require more frequent irrigation for secondary roots to establish and carry the crop through to maturity. Beans are most sensitive to moisture stress during flowering and pod sizing. Water deficit during this period will have the greatest negative impact on yields and pod quality. A balance must be struck however, between maintaining adequate moisture for pod growth while minimizing wetness in the canopy which promotes white and gray molds. After full bloom, irrigate only early in the day to allow for rapid canopy drying whenever possible.
The peak water use for green beans use is approximately 0.20 and 0.16 inches per day for April and June plantings respectively. On most soils, weekly irrigation during the peak is adequate, however with sandy and sandy loam soils, irrigation may be required as frequently as every three to four days.
References:
1. Sanders, D.C. 1993. Vegetable Crop Irrigation, Leaflet No: 33-E (North Carolina State University, Raleigh).
HARVESTING, HANDLING, AND STORAGE
In western Oregon, green bean harvest is generally from about July 10 to the end of September. Wax bean harvest is from about mid-July to mid-September, and Romano beans from the first of August to mid September. The prime harvest season for the Willamette Valley is between July 25 and the end of August for green and wax beans, and between August 1 and 25 for Romano beans.
In eastern Oregon, green beans are harvested from about late July to mid-September.
Yields of snap beans for processing in the Willamette Valley average approximately 6 tons/acre, with good yields at 8 tons/acre.
All beans for processing are machine harvested using tractor-pulled or self-propelled machines that pick three or more rows at a time. New harvesters have picking heads that range from 10 to 15 feet wide.
For processing, harvest is usually started when a graded sample contains about 50% No. 4 sieve size and under. The actual sieve size percentage will vary depending on processor needs and the bean variety.
Grade and sieve size dimensions are as follows:
| Grade | Sieve size | Dimension (64ths of an inch) |
| 1 | 1 | less than 14.5 |
| 1 | 2 | 14.5 to 18.5 |
| 1 | 3 | 18.5 to 21.0 |
| 2 | 4 | 21.0 to 24.0 |
| 3 | 5 | 24.0 to 27.0 |
| 4 | 6 | 27.0 to about 30* |
| Cull | 7 | over about 30** |
* Some companies cap size 6 at 29/64ths, others at 30/64ths. **Some companies cap size 7 at 32 or 33/64ths and consider anything above that a cull. Also, some companies consider sieve size 1 as cull.
Protect harvested beans from heat and sun and deliver to processor or buyer as soon as possible.
Fresh market bean yields are reported to average approximately 35 cwt/acre with good yields at 100 cwt/acre.
Some fresh market beans are machine harvested with tractor-pulled single, or self-propelled multiple-row machines. When fresh market beans are machine harvested, they are further hand sorted and graded before packaging for market.
Photo credit: Bill Mansour, Oregon State University
STORAGE (Quoted or modified from USDA Ag. Handbook 66 and other sources)
Beans intended for processing are not stored and are processed as they are harvested. Protect harvested beans from heat and sun and deliver to the buyer as soon as possible.
For fresh market, or if storage becomes necessary, store at 40 to 45 F and relative humidity of 95%. Green beans should be stored for only a short period (7 to 10 days) between 40 and 45 F. Even these temperatures cause some chilling injury but are best for short storage. Snap beans are cold sensitive and may be severely chill-injured in a few days at temperatures of 38 F and below. Chilled beans develop surface pitting and russeting a day or two after removal to warm temperatures for marketing. Russeting is aggravated by free moisture and is especially noticeable in the centers of containers, where condensed moisture remains.
Beans should not be top iced if they are to be held at higher temperatures later. Snap beans are highly perishable and should be cooled rapidly after harvest, preferably to 40-43 F. They can be effectively vacuum cooled or forced-air cooled, but hydrocooling is preferable not only because cold water cools rapidly but also because the free moisture helps prevent wilting or shriveling. Snap beans lose moisture rapidly if not properly protected by packaging or by a relative humidity of 95% or above. When the relative humidity approaches saturation, as in consumer packages, temperatures above 45 F must be avoided or decay is likely to be serious within a few days.
'Tendergreen' beans can be held for about 2 days at 31 F, 4 days at 35 F, or 12 days at 42 F before chilling injury is induced. Cultivars differ significantly in their sensitivity to chilling.
Beans can be held about 10 days at 40 F if they are utilized immediately after storage, as for processing. Longer storage or holding at temperatures above 45 F will hasten yellowing and the development of fiber. Beans stored too long or at too high a storage temperature are subject to various decays, including water soft rot (Sclerotinia spp.), cottony leak (Pythium butleri), gray mold (Botrytis cinerea), and rhizopus rot (Rhizopus spp.).
Containers of beans should be stacked to allow abundant air circulation. If containers are packed close together, the temperature may rise because of the heat of respiration, and the beans will deteriorate rapidly. When beans are stored in large bins or pallet boxes, provision should be made for rapid cooling. Beans principally benefit from use of a controlled atmosphere (2 to 3% oxygen and 5 to 10% carbon dioxide) because it retards yellowing. Also, the discoloration of broken ends of beans awaiting processing can be controlled by holding them in 20 or 30 % carbon dioxide for 24 hours.
PACKAGING
Beans are commonly packaged in 26 to 3l-lb bushel wirebound crates and bushel hampers; or 20 to 30-lb cartons.