GARDENING : Sprinkle a Day? No Way, Pros Say
Rico Montenegro is frequently amazed at how little people seem to know about watering their lawns and landscaping.
“I have people calling me up all the time wondering why they’re having problems with their lawn. So I start off by asking them how they water,” says Montenegro, assistant director of the Fullerton Arboretum.
And the reply?
Inevitably, according to Montenegro, the response is: “Well, I water every day for five minutes.” And he gets the same response when he asks people how long they water their plants.
Montenegro sighs, and then patiently tries to lead these callers down the path of the most efficient use of water, an increasingly precious resource.
He tells them how water conservation techniques can actually make their plants healthier.
Montenegro readily offers simple tips, handouts and education about drought-tolerant plants that can beautify landscapes and save water too.
“People don’t realize water conservation can take place even with the tropical plants they have,” he says. “Just changing their cultural (watering) practices can save a tremendous amount of water.”
He explains to those daily watering types that “they need to water less frequently for a longer period of time to encourage deeper rooting of plants, be it turf grass, or trees and shrubs.”
Watering every day for five minutes only applies enough water to a lawn to moisten the surface, Montenegro says. “You will continually have a lawn that’s stressed and that’s very shallow rooted.”
A lawn or plant that is stressed will be more susceptible to disease and insect infestation and will suffer more quickly in a drought.
Ever notice how certain plants wilt quickly on a hot day? That’s because too-frequent and shallow watering has brought their roots too close to the surface. And trees in frequently watered lawn areas will be more likely to blow over in a windstorm because their roots are too shallow.
The solution is to wean these plants by gradually watering them less frequently for longer intervals. With trees, a root-feeder (a long, hollow rod available at nurseries for about $20) can be attached to a hose and sunk into the ground for watering to encourage deeper roots. The deeper the roots, the less water a plant requires.
Most lawns, he says, don’t need to be watered more than twice a week. Warm weather grasses such as Bermuda require the least water. The new hybrid fescues, he says, don’t need as much water as cool weather grasses such as bluegrass or rye, but still more than Bermuda.
Cutting grass too short causes shallow roots and requires more care, so Montenegro suggests about 1 1/2 inches high for Bermuda grass and three to four inches for other grasses.
He likens growing plants to raising children: you have to learn and understand their individual needs, he says. Some plants only need to be watered once a month, some two or three times a week. Others may require water once a week or maybe once every couple of weeks.
And how long should you water?
“There’s no easy rule to that because everybody has different soils,” he says. The goal is to saturate the soil, but to stop short of runoff. Sandy soil allows water to penetrate quickly, while soil with a lot of clay becomes saturated too quickly.
“If you have a situation where your soils don’t absorb water readily, then you need to break it (watering) up into cycles,” he says. “If you have an automatic irrigation system, then you would water five or 10 or 15 minutes and then stop, and then you would water again in a short period of time for the same length of time. That allows for deeper penetration of the water and less likelihood of runoff.”
Water-holding capacity for the soil can be improved by adding organic matter, according to Montenegro.
There’s also a new material being used in container planting that retains water. It’s a polymer, sold under the name Broadleaf-P-4. This, polymer, which is available for less than $10, is a granulated material that can be worked into soil. When water is added, the material absorbs it and turns into a gel. As the soil drys out, the moisture is released out of the polymer and back into the soil, so less water is wasted and the soil stays moist longer.
Mulches as top dressings in planting beds and containers both nourish plants and reduce evaporation.
The Fullerton Arboretum uses wood chips, which Montenegro thinks are actually more attractive than bare soil. He says wood chips and compost are probably the best surface dressings to reduce moisture loss and re-nourish plants. Using bark chips or even rocks as a top dressing reduces evaporation. A side benefit is that this also discourages weed growth.
The arboretum gets wood chips from local tree trimmers. The result is a mulch that’s a nice mix of leaves and wood, which will eventually break down and become part of the soil.
Montenegro suggests homeowners check with tree trimmers in their area to see if any are willing to provide a truckload of wood chips. Usually, they pay a fee to dump the chopped up trimmings. Examine the chips before requesting them; they should be fairly uniform, not shredded or in big chunks.
Montenegro also advises adding some form of nitrogen--manure, blood meal or ammonia sulfate--to the soil when using any organic matter that has not been composted as a mulch. Otherwise, the material will rob plants of nutrients as nitrogen is drawn out of the soil during decomposition.
When is the best time to water?
Montenegro’s answer is surprising. Most of us have heard that evenings are ideal because there’s less evaporation. But Montenegro says the best time is in the early morning. Automatic sprinklers, for instance, should be set for 4 or 5 a.m., he says. Water pressure is best then any way.
Evening watering, Montenegro says, creates a cool, moist environment, which is the ideal situation to breed disease and fungi. Plants aren’t growing at night. They’re just sitting in saturated soil.
“By watering in the (early) morning,” he says, “you get the plants the water when they need it. They dry out during the day. When the evening comes, they don’t have the situation with the moisture.”
When it comes to container plants, Montenegro prefers a drip irrigation system because “you are putting water exactly where you need it.”
He’s less enthusiastic about drip irrigation for outdoor ground use because the location of the root system of a plant will shift as it grows. Unless you go back and expand the system as the plant grows, the water won’t be dripping where the roots are. He prefers mini-sprinkler heads, which yield a small volume of water with an even distribution.
When hand-watering container plants, do it slowly. If the soil is very dry and you pour in a lot of water all at once, the soil will not absorb it and much will be lost in runoff.
Container material is a factor here too. Plastic planters hold moisture best, Montenegro says, because they are less porous. Unglazed clay pots and wood containers tend to dry out more quickly.
The type of plant you choose is also a factor in water conservation. One of the goals of the arboretum is to show people how beautiful and how colorful plants appropriate to Southern California’s Mediterranean-type climate can be.
Landscapes Southern California Style in Riverside is a project by the Western Municipal Water District and UC Riverside Cooperative Extension to educate people in the planning, planting and maintenance of landscapes appropriate to Southern California. The one-acre garden at 450 Allesandro Road is on the grounds of the water district.
Tom Ash, director of the garden, is also working on preliminary plans with the Irvine Ranch Water District for a similar garden on land near the San Joaquin Marsh and the district’s water reclamation facility.
The water district, which serves Irvine, parts of Tustin and Newport Beach and some unincorporated areas, already has a small demonstration garden at the Irvine Historical Museum.
A new and much larger garden would create a setting for a comprehensive education program to encourage water conservation, according to Joyce Wegner-Gwidt, public relations manager for the Irvine Ranch Water District and vice president of the Orange County Water Assn.
“We saw this site out in Riverside and were impressed with the concept in that it had working displays of not just plant materials but irrigation systems, mulching, the whole ecological aspect of how you can save water and benefit the environment,” says Wegner-Gwidt.
“Water conservation should be a way of life, no matter what,” she said. “It’s a valuable resource and I think when you live in an area of the country that is . . . subject to the whims of nature, you have to value it. There’s no reason to waste it.”
