The depth of planting should be regulated by the character of the soil; in heavy soils 1« inches is ample, while 2 to 3 is not too deep in the lighter soils. For planting, one-half bushel of the smaller beans an acre is the most common allowance, while some farmers prefer three-fourths of a bushel; from 4 to 6 pecks of the kidney varieties are used an acre.
Field beans are usually planted with grain drills. Either 9 or 11 tube drills may be employed. The operation is explained by the Michigan Station (Michigan Station Bulletin 259, p. 91) as follows: "One of the best machines for planting beans is the ordinary 11-drill grain seeder with 7-inch spaces between the tubes. Stop up all the tubes except the 2d, 6th and 10th and let the drill wheel follow in its own outer wheel mark instead of in the last drill mark, as in sowing grain. This will plant three rows at a time, 28 inches apart, which is about the proper distance. In planting the larger varieties of kidney beans, a bean attachment or special bean drill should be used. Some makes of grain drills have attachments for planting beans." Press wheels on the tubes are valuable to secure a uniform depth of covering and an even stand. Field beans are sometimes grown in hills, but drills are favorable to larger yields.
Earliness is an important factor in the culture of snap beans and both home and commercial gardeners are usually willing to take some risks in getting an early start. The first planting may be killed by frost; but if it escapes the home gardener will be pleased, and the commercial grower will probably be well rewarded. If some of the plants are damaged or killed, those which have escaped may make a profitable crop.
Beans are usually planted with corn drills by the use of the bean plate. Bean "spotters" are also employed to some extent. These drop three or four beans to the hill, the hills being about 8 inches apart. This method of planting gives better opportunity for hand hoeing and is said to increase yields. When planted in drills the beans are 2 to 4 inches apart and covered with 2 inches of soil or less in many instances. No more soil should be used in covering than will insure sufficient moisture for germination. The amount of seed used to the acre varies from ¾ to 1« bushels, depending upon the size of beans and planting distances, but 1 bushel an acre is probably most used.
Pole beans are generally planted in hills, 3 × 4 or 4 × 4 feet apart. The poles are placed at the time of planting. (See Section 311 for notes on methods of supporting.) The hills are often raised a few inches to secure good drainage. Four to six beans are planted in each hill, and then thinned if necessary.
All varieties of lima beans are very tender and must not be planted until the ground is warm and there is no danger of frost. Pole varieties may be grown in hills or in drills, and in the latter case supported by wire (311). The planting distances for pole limas are the same as for pole, snap or shell beans.
Limas are sometimes started in hotbeds or greenhouses, in which case the seed should not be sown longer than four weeks in advance of field planting. Pots or berry baskets may be used for this purpose. They should be filled with light, rich soil and about four beans planted in each pot or basket. By this method the plants may be set in the field without any disturbance of the roots, and edible beans should be obtained at least two weeks sooner than from field plantings.
Poles ranging in length from 7 to 9 feet are generally used for the support of climbing varieties. The bark is left on them, as the rough surface is an advantage to the twining plants. They are placed at the time of planting. If kept under cover when not in use, they will last several years.
Fig. 60. Wire Trellis For Beans.
Various forms of wire supports are used when the beans are planted in drills. This method of support is regarded as an advantage by many growers. Some home gardeners prefer the heavy types of poultry netting, especially for lima varieties. An excellent plan, although more troublesome than the pole method of support, is to plant and brace fairly heavy posts at the ends of the rows with lighter posts at intervals of 20 feet, the posts extending 5 or 6 feet above ground. A No. 10 wire is stretched over the tops of the posts, and another near the ground. The two wires are connected in a zigzag manner with light twine, as shown in Figure 60.
If hard rains occur, causing the soil to bake before the seeds have germinated, the crust should be broken by the use of a weeder. This tool is also used to some extent after the plants are up. Some of the plants may be destroyed, but this is not objectionable if the stand is very good. The least damage to the plants will be done if the weeder is used in the middle of the day, when the stems and leaves are not so rigid.
Thorough tillage is essential to large yields. The weeds must be controlled and the moisture conserved. As the bean is a shallow-rooted plant, deep tillage should be avoided, for it results in root pruning, which is always detrimental to the bean plant. Implements with a large number of narrow teeth or shovels are best adapted to the cultivation of this crop. In the culture of field and garden types on a large scale, riding cultivators are commonly employed. When the plants are small, shields should be used on the cultivators to prevent covering them. The culture should be level until the last cultivation, when wings should be used to throw up a slight ridge for the support of the plants.