In making preparation for sowing or transplanting, harrowing follows plowing. The harrow is also used sometimes by truckers in cultivating after the crops have been started. When used in this manner it is often effective in providing the proper tilth and in destroying small weeds.
Spike-tooth harrows are used more generally than their efficiency justifies, for they are scarcely comparable to some other types in their pulverizing action; their teeth do not run to great depth, and their tendency is to push the clods aside rather than to break them. Smoothing harrows are most valuable, perhaps, when used as weed-ers after a crop like potatoes or sweet corn has been started. The spring-tooth harrow is an important tool among gardeners, being especially well adapted to stony ground. It is also an excellent pulverizer and leveler. Disk and cutaway disk harrows are exceedingly valuable implements as pulverizers, and are especially useful for clay soils and for reducing heavy sods. When heavily weighted they cut to great depth. Disking is sometimes practiced before plowing. This preliminary operation is regarded by some as being of special value in truck farming. Manure can be applied, and then chopped up and worked into the soil before plowing. This method results in fine soil to the full depth of the plow furrow, if harrowing after plowing is done as thoroughly as it should be. The disk harrow is unquestionably the best pulverizing tool for the heavier soil types and is far superior to the spring-tooth harrow in most soils. The Acme harrow is prized by many vegetable growers because it not only pulverizes to a considerable depth, but it has also good leveling action. The Meeker smoothing harrow, which has 58 disks mounted on four rollers, is practically indispensable in vegetable gardening as a finishing harrow and should be used exclusively for this purpose. It does the work of a steel garden rake, though better and more economically, and not only pulverizes to the depth of 3 or 4 inches, crushing even the smallest clods, but by an adjustable plank running across the middle of the harrow it also levels and leaves the soil in the smoothest possible condition for sowing or transplanting. It is an old harrow, but not as generally used as it should be.
The efficiency of harrowing depends not only upon the adaptation of the implement to the work to be performed, but also upon the moisture content of the soil at the time of operation. If too dry, a large percentage of the clods will not be broken and if too wet great injury will be caused in puddling. Closer attention should be given this matter by all classes of cultivators. A common occurrence is to plow land and let it lie for many days without harrowing. Except for fall plowing no greater mistake can be made, for during the interval between plowing and harrowing an enormous amount of soil moisture escapes and thorough pulverization of the soil when dried is almost impossible. No more land should be plowed than can be harrowed at least once the same day.