After the vines are planted, or when irrigation is necessary, one or more furrows are plowed on each side of the vine, and the water is allowed to run in them for several hours, or even days, until the soil is sufficiently soaked. In many places three furrows are made between the rows of vines, and the water is allowed to run in at one end and out through the other in a stream only sufficiently large to cause all the water to sink. Where particular nicety is required, the waste water which runs out at the farther end may be collected in a trough with perforated holes, through which it is conducted to a ditch or lower check. Similarly, a long trough may be used for conducting the water to the land in the first instance, and allow it to run out through a number of small holes, one of which is situated in front of every furrow. When the ground is well prepared, level and with an even slope, this system of irrigation is very perfect, and causes but little expense and trouble in management. In Riverside the vines are irrigated thus every three or five weeks, while in Redlands less irrigation is used on old vines. As a rule, in Southern California the furrowing system is the accepted one as being best adapted to the nature of the country. The water is conducted both in open ditches and in pipes, and when under pressure saves much labor and expense which would otherwise be required for the continued construction and repair of ditches. The furrowing system has, however, its disadvantages. It requires a longer time to fill the soil sufficiently, and accordingly it takes many more irrigations to accomplish as much as with flooding. As advantages of this system, we might state that it requires no banks or levees to back up the water, and a vineyard irrigated this way can be kept entirely free from weeds by a few cultivations, while a checked vineyard must besides be cleared with hand labor, as the banks and checks are apt to be destroyed by cultivation.