Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, March 15, 1990< TAG: 9104050031
SECTION: LAWN & GARDEN PAGE: 4 EDITION: EVENING
SOURCE: Charles Stebbins / Correspondent
DATELINE: LENGTH: Medium
Water-saving drip irrigation, also known as trickle irrigation, is a simple system involving a perforated hose or pipe with the end capped off, laid atop the soil along a row of plants. The small holes allow water to seep out into the soil.
"This puts the water where it's needed," said Shelly Kapitan, a horticulturist with the Virginia Tech Extension Service in Roanoke County.
The drip method can be a benefit if a homeowner has a well with a relatively low output, she said. It draws water more slowly from the well and wastes less.
Not only does the drip method save water, it also keeps the foliage of plants dry.
"Wet leaves are a good place for diseases," said Dennis Jamison, a Roanoke Valley farmer and orchardist who uses drip irrigation on his family's Grandin Road Extension farm in Roanoke County.
Many fungus ailments of a number of plants thrive in damp foliage. And sprinkler-soaked foliage is a good environment for scab, mildew, brown rot and the likes.
In addition, Jamison noted that much water sprayed into the air evaporates before it gets to the leaves.
Jamison said his operation uses drip irrigation extensively on tomatoes and that he is now experimenting with it in a blueberry patch.
Drip irrigation also is valuable on young fruit trees until they get established, he said.
Another way Jamison's farm uses drip is with newly planted seeds and seedlings early in the season.
The drip hose is laid along the row and a plastic cover is put over the hose and the small plants or planted seeds. This holds in moisture and warmth and keeps out chilly winds, frosts, bugs and other hostile elements.
The plastic is removed after the weather gets warm and the plants are established.
The drip method has one disadvantage that can make it inoperable in some cases.
Some drip systems are nothing more than plastic hoses with a number of tiny holes. Problems can arise if the holes become clogged by minerals of sediment.
"With a system in which the water drips out, you need awfully clean water," said Lowell Gobble, also with the extension service in Roanoke County.
Many drip pipes are designed so water sweats through all surfaces of the pipe. A more elaborate way to avoid clogging is to use a pulse system in which the water is under high pressure. The pressure keeps the holes open, Gobble said.
Homeowners with small gardens can create modified drip systems with little expense or effort.
For single or isolated plants, plastic gallon jugs or buckets with several small holes in the bottom will work. Fill the container with water and then set it on the soil close to the plant.
Another simple method uses an ordinary garden hose. But this requires more effort and presents problems.
A hose laid in the garden puts all the water in one place and can cause serious washing of soil unless the water is running very slowly. The hose must be moved many times to get water throughout the garden. And even then it probably won't be distributed evenly.
A way to minimize the washing problem would be to put a cap on the end of the hose and leave it loose enough so that it leaks slowly.
A drip irrigation system may not always be economical, according to Diane Relf, a horticulture specialist with the Virginia Tech Extension Service in Blacksburg.
If a water supply is not handy to the garden, Relf said, the cost of installing one for a drip system must be weighed against the expected value of the crop. The cost could consume most of the profits gained from the garden, she said.
by CNB