There are watering systems that release water very slowly at soil level and do not allow any water to get on the leaves of the plants. These drip or soaker irrigation systems, as they are called, offer a number of important benefits to the yard and garden. They are not appropriate for watering lawns, but they are preferred methods for watering flower beds, vegetable gardens, trees and shrubs.
First and foremost, these systems use much less water than the overhead sprinkler. You can assume that you will save at least 30 percent, and in some cases 50 percent, of your water over sprinklers or other methods of watering. Water delivered by a drip or soaker system has no chance to evaporate or run off, because it is completely absorbed by the soil and never touches the leaves of the plants.
Research has demonstrated that drip or soaker irrigation systems, especially those used in conjunction with mulch, increase the plant's performance. Plants show earlier blossoming, increased growth, and larger blooms. Because the water never touches plant leaves, they avoid many moisture-related diseases. Problems such as rust, mildew, and blossom damage are all reduced in gardens using a drip technique.
Another advantage is the cooling effect a drip or soaker system has on the soil. A properly managed drip or soaker irrigation system can be used to help keep down soil temperatures in the high heat of summer. This increases production, because plants grow more effectively in the cooler soil.
Finally, a drip or soaker irrigation system reduces the problem of soil compaction. When the soil is saturated with large amounts of water, its structure breaks down and compaction occurs. Drip or soaker irrigation reduces this problem because the water is introduced into the soil so slowly that the structure of the soil is not affected.
With no adjustments needed for evaporation and run off, you can plan your watering task around the need to get about one inch of water to your plants each week from rain or from your drip system. That is about two quarts of water per square foot of garden per week. All you have to do is find out how much water your particular drip or soaker system releases over time, and you can then calculate how long each day or every two or three days you need to run your system. The trick is to set an empty tuna fish or cat food can under the drip emitter or the soaker hose. Time how long it takes to fill the can and you have the time it takes to get an inch of water approximately.
Pressure vs. Volume
Most drip or soaker systems require a reduction in the normal household water pressure to operate properly. In addition, some systems require a reduction in the volume of the water coming into the system. You must be sure, when buying your drip irrigation system to insure you have the proper pressure reduction device, and a volume reduction device if it is needed. A soaker hose system needs neither device. You simply turn your faucet on just a little bit, maybe a half a turn and you effectively reduce the water pressure and volume going into the soaker hose.
The issue here is to keep water pressure high enough so that water drips out of the system at the same volume along the entire length of the hose. You do not want a lot of water near the house and very little water farthest away from the house.
Most drip or soaker lines irrigate a 2-foot-wide strip, about 12 inches on either side of the drip line. That means if you lay two lines 24 inches apart water will reach the roots of all the plants or shrubs in a 4 foot wide bed. Of course this estimate assumes you have normal, loamy soil. If your soil tends to be sandy and drains very quickly, place your lines just 18 to 20 inches apart to make sure all the plants are well irrigated. You can set up a drip system for a 200 square foot garden in an hour or two. A soaker system can be set up in 30 minutes.
A drip or soaker irrigation system is not cheap. However, these systems, if properly cared for, will last for at least a decade with very little maintenance.