Note Number: AG0197
Published: September 1994
Updated: May 2013
The common or garden bean (Phaseolus vulgaris) is a native of Central America. The fresh bean, the immature succulent pods of "French Beans", may be green or wax (butter) or purple-coloured. The pods may be "stringed" or "stringless" (also called "snap"). They may be sold on the market or processed to be frozen, canned or dehydrated. The stringless varieties are used for processing and for the fresh market. Most are dwarf bushes, but climbing varieties are popular among home gardeners.
Beans are frost-prone warm-season plants needing from 60 to 80 days from sowing to first pick. They will not tolerate wind, heat with low humidity, or low temperatures. The results are poor growth, blossom-drop, poor pod-set and hollow, short and deformed pods.
Beans are very sensitive to wind, and windbreaks placed around the crop and strategically within the crop reduces wind effects and maintains temperatures.
The temperatures for germination are from 16°C to 35°C, the optimum 26°C; for growth and quality the optimum monthly average (day and night) is from 16°C to 21°C.
Beans suffer from waterlogging but need adequate moisture throughout. They need mild, moist weather or irrigation, especially at flowering time. Rain just after sowing can cause poor germination, and prolonged rain after petal-fall is ideal for the development of bacterial blights and Sclerotinia white rot.
Soil and fertilisers
Beans need well drained deep friable self-mulching loams, sands or peat soils, containing ample organic matter. Moderate to slightly acidic soils (pH 5.5-6.6) are ideal, and, where acidity may be slight, 500 kg per hectare of 5050 super-lime drilled in with the seed as a band is the recommended practice.
In East Gippsland, the main production area, beans thrive on land broken up from pasture or following maize or an Italian ryegrass green manure crop. On the fertile alluvial soils about 250 kg superphosphate per hectare, or similar, is drilled in a band with the seed. On less fertile soils, about 250 kg of NPK 8:11:10 per hectare, or similar is drilled in as a band separate from the seed. The fertiliser will burn the germinating seed if it contacts it.
When the fertiliser is broadcast, three times the above rates are used. Excess nitrogen produces too many leaves which hamper and delay harvesting; and the crop suffers in hot dry weather without adequate irrigation. Side-dressings of fertiliser are seldom applied.
Seed and sowing
Beans are sown from early October to mid-March depending on the climate. Seed of good germination, vigorous and free from seed-borne diseases must be used. The seed bed must be firm and have a crumbly surface; it must be moist but not too wet. The seed is sown from 20 to 40 mm deep, depending on the prevailing weather. If planted too deep in wet, cold soils the seed may fail to germinate or may be prone to attack by soil fungi or seed-corn maggots.
Generally, the beans are sown in rows around 500 mm apart and between 50-100 mm between plants.
It is important to realise the effects that plant population and seed size have on the sowing rate. If seed are small (3000 per kg) and sown at a spacing 50 x 750 mm, 90 kg of seed is needed per hectare. For larger seed (1500 per kg), 180 kg of seed is needed per hectare if germination is 100%.
The germination percentage should also be taken into account when planning the planting density.
Two-row or four-row seeders, specially built for beans or sweet corn, are used. They place the fertiliser with the seed and can be fitted with a pre-emergence herbicide applicator behind the drill.
There are hundreds of bean cultivars available and a wide range of cultivars are used commercially. Some of the cultivars commonly grown include Bronco, Labrador, Broker, Idelite, Jade, Sonatra (round stringless), Pioneer and Hurricane (flat stringless) and Buttercrisp. However, new seed cultivars are being continually released and this is not a complete list. Other varieties such as stringed beans Windsor Long pod, Redland Pioneer and climbing beans All herbicides must be applied strictly according to the are generally grown for home gardens. directions on the label.
Basic land preparations should be carried out early enough to allow existing weeds to be buried or killed so that a firm, weed-free seed bed is obtained before sowing. Hasty preparation of seed beds often leads to serious weed problems during crop establishment; these cannot be overcome by the use of pre-emergence herbicides.
Both pre-emergent and post-emergent herbicides may be used to control weeds in beans. Your herbicide program must be based primarily on the weed species expected to appear in the particular paddock you are cropping.
Select the herbicide carefully, read the label and follow all the label instructions.
Different herbicides are neded, where annual grasses are a problem, compared to where blackberry nightshade is a problem.
Other herbicides may be used immediately after sowing.
Once the beans have developed two trifoliate leaves, certain broad leaf weeds, in particular thornapple, can be controlled with "Basagran". "Basagran" will not control grasses.
When herbicides are not used, the beans need to be scarified soon after emergence. Deep scarifying will prune the roots, setting the plants back, and high hilling will bury plants and interfere with machine harvesting.
Pests and diseases
Aphids, leaf-hoppers, two-spotted (red spider) mites, weevil, seed-corn maggot and Helicoverpa caterpillars are pests. Diseases are summer death, subterranean clover stunt virus, yellow bean mosaic virus, halo blight, common blight, syringae blight, sclerotinia white rot, anthracnose, rust, angular leaf spot and damping-off.
Fresh beans for market are hand-picked or machine harvested. Hand-picked crops are harvested two or three times while machine harvested crops have only one pick.
For processing, beans are harvested with two-row or multi-row machines; a once-over harvest of 1 hectare takes about two-and-a-half hours.
A crop should yield from 6 to 12 tonnes per hectare. Hand harvested crops will yield more due to the greater number of picks. Beans are now more commonly marketed in a 10 kg carton rather than the more traditional 20 kg sack.
This agnote was developed by Robert Dimsey, September 1994.
It was reviewed in May 2013.
Published and Authorised by:
Department of Environment and Primary Industries
1 Spring Street
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