Snap beans grow best in full sun (they are tolerant of light shade) in a moist, well-drained, friable and moderately fertile soil.
Sandy loam soils which are loose and warm rapidly in spring are preferred, but beans can be grown successfully on heavier clay or organic soils provided the soil is properly prepared and well managed. This may include mixing in some coarse sand to loosen the soil to improve drainage and aeration.
Snap beans make best use of fertilizers if the pH is 6.0 to 6.5. When lime and/or fertilizer is applied, till it six to eight inches deep just prior to planting. Break up large clods of soil and rake the area smooth.
Snap beans are the most popular bean, and many of the varieties are stringless. Beans have a short growing season and are harvested when the pods are immature. The snap bean is a member of the legume family and has the ability to fix atmospheric nitrogen in its roots. However, beans do not remain in the ground long enough to be effective in producing nitrogen-fixing nodules.
Snap beans are either bush or pole types. Bush types are self-supporting plants that grow one to two feet high, while pole types produce vines that require support such as stakes or a trellis.
|Bush-Green||Bush Blue Lake, Greensleeves, Provider, Tenderpod, Greencrop, Roma, Derby|
|Bush-Yellow||Slenderwax, Goldcrop, Golden Butter Wax, Gold Rush|
|Pole||Romano, Blue Lake, Rust Resistant Kentucky Wonder, French Horticultural|
Snap beans are a warm season crop that grows best when the mean temperature is between 70o and 85oF. Temperatures that are too high can cause plants to drop blossoms. Germination is delayed when soil temperature is below 65oF. In most parts of Connecticut, planting of snap beans can be done successfully in mid- to late May.
The bush-type varieties are usually planted in rows. For single rows with 18 to 30 inches between rows, the seeds are sown one to two inches apart, and seedlings are thinned to two inches apart. For wide row plantings that are 18 inches wide, the seeds are placed three to four inches apart in all directions.
The pole varieties are planted in rows two to four feet apart with seeds spaced one to two inches apart. Use stakes or a trellis to hold vines from falling to the ground. Pole varieties are also planted in hills three feet apart in all directions. Sow six to eight seeds in each hill and thin to three to four strongest plants to a hill.
Snap beans have large seeds which are sown 1 to 11/2 inches deep. Successive plantings of bush-type varieties at two-week intervals can prolong the harvest season.
Weeds are controlled easily in the seedling stage by shallow cultivation. Do not cultivate too deep because bean roots are close to the surface.
A two- to four-inch layer of mulching material such as straw, weed-free hay, mulch, lawn clippings or other loose organic material can be effective against annual weeds if it is applied to weed-free soil. Black plastic stops all weed growth and may hasten bean growth by warming the soil.
Beans are sensitive to both dry and wet conditions. Too much or too little water can cause beans to drop their flower buds or pods. Keep the soil evenly moist. An inch of water per week is needed during the growing season. This will moisten the soil to a depth of six to 12 inches.
Snap beans are harvested as immature pods before the seeds are well developed. At this stage, they have the best flavor and nutritional value. Beans must be picked two times a week to ensure a continuous harvest. If pods are allowed to mature, the plant will stop blooming.
Insects, Diseases and Other Pests
Snap beans are attacked by many insects and diseases and their damage can be serious at times. However, problems are best controlled by some preventive measures such as planting disease-resistant varieties or disease-free seeds, removing and destroying all diseased plants in and near the garden, using crop rotation, not handling plants when the foliage is wet, and keeping the garden and surrounding areas free of debris and weeds.
Chemical control is another way to combat diseases and insects. However, it should be used only after all other methods have failed. (See chart.)
|Anthracnose||Pods: Brown to black sunken circular spots. Under moist conditions, spots may have pink color. Leaves: Dark reddish-brown to black area on veins. Stem: Elongated rust colored lesions||Grow resistant varieties. Till in debris in the fall. Avoid overcrowding. Apply fungicides at flower initiation, late flowering and pod fill stages. Use copper compounds, chlorothalonil or maneb.|
|Bacterial Blight||Leaves: Small, water-soaked areas developing into larger, reddish-brown areas. Stems and pods: Deeply sunken lesions surrounded by reddish-brown tissue.||Plant western-grown seed. Stay out of garden when plants are wet. Till in debris in the fall. Apply copper sprays (cupric hydroxide) when disease is noticed|
|Mosaic viruses||Yellow mottling of leaves. Deformed leaves and stunting of plant Blossoms may drop.||Grow resistant varieties. Control aphids and leafhoppers which carry viruses.|
|Powdery Mildew||Powdery white growth on leaves, stems and occasionally pods. Affected parts often shriveled and distorted.||Grow resistant varieties. Avoid overcrowding. Provide adequate air flow. Apply sulfur weekly during periods of high humidity.|
|Rust||Small, whitish, slightly raised pustules on the underside of the leaves turning a reddish-brown. These discharge the rusty colored dust-like spores. More of a problem in hot, humid weather with heavy morning dew.||Maintain good air circulation. Apply a fungicide when weather conditions are favorable for disease development. Use chlorothalonil or sulfur. Weekly applications may be necessary.|
|White mold Sclerotinia||Water soaked spots appear on stems, leaves and branches about seven days after bloom. A white cottony mass develops in which small black hard bodies appear. Leaves yellow, brown and fail off.||Provide good air circulation in well-drained soil. Apply fungicide at first bloom--benomyl, sulfur or thiophanate-methyl.|
|Mexican Bean Beetle||About 1/4" long, coppery brown color. Eight black spots on each wing. Small yellow eggs. The larva is a yellow spiny grub usually found on the underside of leaves.||Clean debris from and near the garden where the adults overwinter. Control insects with rotenone, acephate, malathion, carbaryl, diatect, diazinon, pyrenone, pyrellin or methoxychlor.|
|Aphids||Small green, yellow or black sucking insects found near the new growth. Heavy feeding causes curling on the foliage and presence of honeydew which turns black from sooty mold.||Apply acephate, insecticidal soap, diatect, diazinon, malathion, naturgro, ultraftne petroleum oil, pyrellin, pyrenone or rotenone when the insects are noticed.|
|Leafhoppers||Small light-brown to gray insects about 1/8" long which hop when disturbed. Capable of transmitting viruses.||Control weeds in and near the garden. Apply acephate, Diatect, diazinon, malathion, insecticidal soap, natur-gro, ultrafine petroleum oil, pyrellin, pyrenone or rotenone when the insects are noticed.|
|Mites or Red Spiders||Very small, light-colored or reddish. Small white spots on leaves where mites have fed. Heavy feeding damage will cause the foliage to brown. Webs are present when mite populations are high.||Apply diatect, diazinon, dicofol, malathion, insecticidal soap, ultrafine petroleum oil, propargite or pyrellin when mites are noticed.|
|Bacterial Blights and Anthracnose||Root Rots|
The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.