Too many seem to conclude that the main purpose of cultivation is the destruction of weeds. But the fact must be recognized that the dust-blanket between rows, frequently stirred by hand or horse cultivator, conserves the soil moisture in the early part of the season and the precipitation of summer showers later in the season. In connection with deep fall plowing and subsoiling the surface culture not only conserves moisture, but it admits atmospheric air and warmth. In other words, it favors what King calls soil ventilation, and in addition it furnishes the needed conditions favorable for surface root action in taking up nitrates and liquid plant-food.
The selection of tools for culture in. growing crops is also important. A harrow, if it runs deep in mellow soil, conserves, soil moisture. But on soils firmed by rains its scratching and cutting the surface only hastens evaporation. If not properly set and followed by harrowing to level the surface, it is the same with the disc harrow. When it opens wide grooves and leaves hard ridges between, its use increases rather than retards evaporation.
Fig. 102. - Planet Junior cultivator with pulverizer.
The thought to be kept in mind is that a fine tilth to the depth of three inches on established crops should be continuous to hold moisture.
Bailey aptly says: "We neglect the saving of the early rains, and gamble on the chance of having a rain when we need it. It often happens that the dry countries suffer least for water. How shall we save the water ? By holding it in the earth. If the earth is finely divided and yet compact, the capillary pores or interstices will hold enormous quantities of water. If, then, we break up these interstices next the atmosphere, we shall prevent the water passing off by evaporation."
When the plants are young, hand and horse cultivators are used that throw very little dirt sidewise. These, such as the Planet Junior, can be run very close to the plants (Fig. 102). The different classes of horse hoes are mainly for use later in the season, in corn, potatoes, and other coarser crops in rows wide enough apart for horse culture,
The hand cultivators - of which there are many good patterns - are mainly used in commercial gardens between rows of beets, lettuce, onions, bush-beans, and other small growers planted only sixteen to eighteen inches apart, as illustrated in Fig. 103, which shows the use of attachment shovels for both opening a furrow between narrow rows and then, by going a second time over the rows, closing and leveling the furrow.
Fig. 103. - Hand cultivators with shovels to open and close furrows. (After Green.)
The hand cultivators are also used to great advantage in small gardens in city lots, where a horse cannot be used to advantage. But in farm and suburban-lot gardens, where horse culture can be used, they do not pay.
Small-growing plants, such as beets, parsnips, onions, lettuce, and radish, are planted in double rows about sixteen inches apart. The horse cultivator is run outside of rows on each side, and between the rows the hand hoe is used, or a hand cultivator if one is owned. But the quantity of such vegetables grown for ordinary family use is too limited to justify its use, as the culture on one side of each row will give the needed conditions for growth if the soil is kept in gardening condition.
It is also usual to plant garden peas and sweet peas in double rows about the same distance apart, using the horse cultivator only on one side of each row, and using the hoe between.