A Drip At A Time -- Gardeners Can Install Irrigation Systems To Control Water Delivery For Different Plants

CUTLINE: LISA REMILLARD / SEATTLE TIMES: DRIP IRRIGATION FOR HOME GARDENERS -- CONSERVES WATER AND ALLOWS PLANTS TO RECEIVE WATER BASED ON THEIR NEEDS (DRAWING OF SHRUBS AND PART OF A GARDEN)

Irrigation brings to mind the Yakima Valley where, thanks to piped-in water, the desert blooms with grapes, apples, mint and hops.

But for growers of the humble home variety, watering the garden means early-morning sprints across a soggy lawn to move the sprinkler or startling from the brink of sleep to the hum of a forgotten hose.

Now, you can rest peacefully.

Borrowing technology from commercial irrigation, but scaling it down for home-garden use, there are inexpensive systems that don't take an Albert Einstein to install. They use plastic tubing with tiny devices that drip regulated amounts of water to the base of each plant, providing benefits of increased yield and decreased water waste. You can even put a timer on them.

Despite Seattle's reputation as rain city - June was almost a record breaker for precipitation - the summers around Puget Sound actually are dry. Droughts lurk in recent memory.

Water rates and water shortages should be enough to make gardeners have serious thoughts about conservation. But water conservation isn't the only benefit from drip irrigation.

John Kaye, one of the Northwest's leading experts on drip irrigation, was in Seattle recently at a Tilth Association workshop on

irrigation.

He compares drip irrigation to intravenous feedings for hospital patients. Instead of a huge glut of water that can't be digested, plants receive a carefully modulated supply based on their needs.

Drip irrigation is relatively new to home gardeners in this area, but Kaye's coaching has helped several home gardeners install their own systems. About 30 showed for Kaye's most recent pep talk.

Kaye, owner of Modern Agri-Products in Ferndale, usually deals with commercial growers, but he's convinced that anyone can install a drip irrigation system if he or she follows a few basic rules and doesn't get scared off by some simple calculations. One of Kaye's students put in her system in two days.

Kaye points out that watering the garden, whether it's flowers or vegetables, is essential in Western Washington from June to September.

Most gardeners take a shotgun approach to how much water their gardens actually need. The cycle of neglect and overcompensation leaves plants under siege, Kaye says.

Overhead watering is the main alternative to drip. Overhead sprinklers lose water to evaporation, crust the soil surface and wet leaves and stems, which can promote fungal diseases.

Improper watering can harm garden soil. Waterlogged soil is less productive. It can't breath, so harmful fungi and molds thrive, causing roots to rot.

Too much water causes packing and makes clay soils stick together. All this adds up to stress for plants and gardeners.

Dry soil is just as bad. Root hairs die. The soil gets too hot. Worms and healthy organisms find better ground.

Ah, but a constant soil moisture helps the good guys - soil organisms - thrive, and they in turn create humus, which makes the soil loose, fluffy and absorbent.

Drip irrigation, which delivers small amounts of water over a long period of time, increases yields by 25 percent, Kaye says.

For the footloose and carefree, a drip-irrigation system and an inexpensive timer also make it possible to have your garden and travel, too.

Vacation, says Gil Schieber, was the impetus for installing a drip irrigation system at his home garden in Ballard. When Schieber and his wife were planning a trip to England two years ago, they installed an extensive system of drip tubing, microsprayers and a computerized timer connected to their hose bib.

The plastic feeder lines and most of the tubing that carry the water directly to plants are buried a few inches below ground. Because he has a variety of minigardens ranging from herbs and perennials to tomatoes, lettuce and beans, Schieber has set up different irrigation lines for each garden zone.

The result is an urban oasis where drought-tolerant plants live side by side with water-hungry vegetables.

Schieber estimates that it would cost less than $100 to install several zones of drip irrigation in a typical garden.

Schieber's garden is not typical. He turned under the entire lawn in his front and back yards three years ago and hauled in 60 truckloads of manure.

Now poppies grow shoulder high, and sixth-generation lettuce bulges beneath towering oats and stipa grass.

``This garden is all about thinning,'' says Schieber, who has 200 new plants to add from his excursion to England this year. Schieber collects and cultivates rare plants, like his squatty evergreen from South Africa and black iris from Britain.

The beauty of drip irrigation is that it frees you to enjoy your garden, says Schieber as he grabs a handful of glistening June berries.

``I better get these before the birds find them,'' he says, popping them in his mouth like a child with bubblegum.

Schieber also helped install a drip-irrigation system at Seattle Tilth Association's demonstration gardens. The Good Shepherd gardens and nursery at 4649 N. Sunnyside Ave. are open to the public, and they provide lush testimony to the benefits of drip irrigation.

So far so good, you say. But letting the hose run for hours while you fall asleep watching television sounds a lot more natural than trying to figure out how much water those tomatoes and beans need.

That's right, to design your drip-irrigation system you need to figure out how much water to give each plant.

Math-phobics may skip plan A and go directly to a garden store to purchase a kit that contains all the parts necessary for a vegetable patch or flower bed.

But if you still know how to tie your shoes, you probably can do a little adding and multiplying.

Instead of getting bogged down with complex formulas, Kaye encourages gardeners to use the water needs of these typical plants to figure a watering plan:

A dwarf apple tree, for example, needs about five gallons of water per day. Emitters drip water at a rate of one gallon per hour. Therefore, you need to install five emitters in the drip hose around the tree and let it run for an hour.

A raspberry bush needs 1.7 gallons per day, a tomato plant needs about 1 gallon per day and a strawberry plant takes half a gallon per day. More extensive charts on water needs are available through drip-irrigation equipment suppliers, but generally need is dictated by the size of the plant.

Because different plants have different water needs, you may want to use a separate drip line for groups of similar plants. The amount of water that a vegetable garden needs may drown young herbs.

Along with the type of plants and their root structure, you need to consider the type of soil. Sandy soil sucks water down. In finer soils such as clay, the water will spread out rather than down. Kaye says sandy soil needs to be watered more frequently. It can only hold a water reserve for two days, but loamy soil can go for four days between watering and clay soil will hold a water reserve for nine days.

To design your irrigation system, it helps to make a scale drawing of the landscaping and plantings you want to reach with drip irrigation.

After sketching in where the emitters and tubes will go, calculate the number of parts you will need.

Start from the plants and work backward to the hose bib. Don't worry about making a mistake. The flexible plastic tubing used for drip irrigation can be easily plugged if you find out that a plant is getting too much water. Likewise, it's simple to punch a hole for additional emitters later.

The tubing itself is easy to extend by slicing and inserting more tubing.

Along with emitters, you may want to use microsprinklers and microsprayers, which come in a variety of spray patterns from 45 to 360 degrees.

Some drip-irrigation tubing is similar to soaker hoses. But unlike soaker hoses, drip irrigation can compensate for changes in water pressure so water is distributed evenly on long runs or over steep hills like those fronting many Seattle homes.

If the elevation change in your yard is more than 20 feet, Kaye says, you'll need pressure-compensating emitters. As you design your system, keep in mind that elevation and friction affect pressure. Pressure is always lost as water travels through tubing. Elevation can add to pressure if the tubing runs downhill or reduce pressure if the system runs uphill.

Drip components are designed for low water pressure. They will malfunction and break with normal household pressure. You can avoid problems by attaching a pressure regulator to your hose bib.

The pressure regulator, filter and back-flow valve are essential parts for the head. They are attached from the water faucet to a header hose that takes the water out to the drip lines.

If you want to put in the system and put watering completely out of your mind, consider using solenoid valves, which are battery-operated minicomputers that turn the water on and off.

There's a variety of drip-irrigation systems on the market. Wallingford Garden Center in Seattle and Molbak's Nursery in Woodinville both have drip-irrigation supplies. The kits are about $25 to $30. You can buy the tubing separately and add your own emitters.

Mike Duffy of Molbak's says 50 feet of drip tubing costs about $15. He said it's economical and more convenient than dragging hoses around.

If you are serious about saving money and building your system from scratch, Howard Stenn, a local landscape consultant, suggests Sherman Pipe and Salvage Company, 2456 First St. S.

Schieber says he goes to Steuber Distributing Co. in downtown Snohomish, where he gets 100 emitters for $1.50.

Whether you use a kit or assemble the components yourself, look for a drip tube that doesn't clog and is easy to clean. Then be sure to flush out the system to keep lines clean and free of dirt. A filter can keep emitters from clogging and it's worth investing in a good one if you want to keep maintenance at a minimum.

Mail-order suppliers also carry extensive lists of drip-irrigation components. These companies are recommended by Schieber and Kaye:

Harmony Farm Supply, P.O. Box 451, Graton, CA 95444. Catalog $2. (707) 823-9125.

The Urban Farmer Store, 2833 Vicente St., San Francisco, CA 94116, Drip Irrigation Catalog $1. (415) 661-2204.