City of San Luis Obispo - Utilities Department

Dripping Faucet OUTDOOR WATER CONSERVATION
Most residential customers are unaware of how much water they use for irrigation. For example, during warmer months, each 100 square feet of your lawn may require 374 gallons (one/half billing unit) of water per 30 day billing period. This handout provides brief ideas that will help you maintain a thriving landscape while conserving water and reducing your water bill.

Irrigation

Water only when your lawn needs it. An Irrigation Schedule is available online or from the Utilities Conservation Office. It can be used to set up an effective watering plan.

For the dedicated gardener, the best way to adjust your irrigation frequency is to walk through your yard every afternoon, before dark. If you notice a dull caste to an otherwise healthy lawn, your lawn may be showing signs of water stress, and should be irrigated before the next day. The dull cast is a result of the grass blades rolling up due to poor soil moisture. Don’t check for stress in the mornings, as stressed lawn will often recover overnight, only to severely die back during the heat of the next day.

You don’t want to stress your lawn all the time, so you can use the information you have gathered to adjust your irrigation frequency. For example, if your lawn showed stress on the third day after your last irrigation, then you should adjust your irrigation schedule so that you irrigate the evening of the second day or the morning of the third day to reduce the stress to the lawn. Your lawn’s needs will change as the weather heats up or cools, so you will want to make appropriate adjustments. Be sure to consult the City’s Irrigation Schedule for an estimate of how long you should water each time (duration), and how often you should water (frequency) for a given season.

Planning Your Landscape

Amend your soil before planting. San Luis Obispo tends to have a hard, relatively impermeable soil. You can improve your soil by adding organic matter such as compost, grass, leaves, or a commercial soil amendment. Adding organic matter to your soil will improve your soil’s percolation rate and water retention, it will also improve the health of your landscape. Most of a plant is found underground, so the health of your soil is a huge factor in the health of your landscape.

Plant landscapes during the fall (make sure they can endure the winter cold). You will be able to establish your plants almost entirely with seasonal rains. Grass seed has difficulty germinating in cold weather, so lawns are the exception; they should be seeded in early fall.

Group plants in hydro zones, according to their water needs, especially if you have an automatic irrigation timer. If you irrigate thirsty plants and drought tolerant plants from the same station, you will need to over water the drought tolerant plants to assure enough moisture for the other plants. If you inherited an existing landscape, this problem may be eased by placing adjustable drip irrigation on the plants. Adjust each emitter appropriately for the vegetation type it will water. Consider planting winter blooming or early season bulbs. Although they die back with the warm season, they will return each year and thrive on rain water alone.

Maintenance

Keep your lawn trimmed to a longer length (two or three inches). Lawn mower. The longer grass will encourage deep roots, and it will shade the underlying soil; reducing water loss through evaporation. Bermuda grass is an exception; it should be trimmed relatively short.

How often do you fertilize? Additional water will not always produce a greener or healthier landscape; sometimes all that is needed is shot of fertilizer. Be sure to follow the directions, because some fertilizers can harm your plants if they are not applied properly.

Slow release fertilizer is good, and organic fertilizer is better. Organic fertilizers are most effective during spring, summer and fall months. Other fertilizers tend to be faster acting, but they may not be as good for your soil. Avoid “weed & feed” fertilizers and garden insecticides when not necessary. They can destabilize the health of your soil.

TIPS

Be sure your sprinklers are irrigating your plants, and not the surrounding pavement. Adjustable angle spray heads are available for most sprinklers, and they can help prevent this overspray. A tilting sprinkler head can also be a source of overspray. Make sure sprinkler heads in border areas are vertical, and do not angle back to cause problems.

Over spray can best be prevented during the design phase. If you plan to plant a lawn that curves and is next to a sidewalk, you will have an over spray problem, because the water cannot be adjusted to the uneven border. If you want a curved lawn, consider creating a buffer zone by moving the lawn back from the paved area. The sprinklers can be installed on the edge of the lawn, and any overspray will land in the buffer zone; not the sidewalk or street.

Lawns require a tremendous amount of water. Consider limiting lawns to areas where they will be used. A shaded lawn may require only 1/3 as much water as a lawn exposed to the sun. If you are planning a lawn, consider adding a shade tree, and designing the lawn so that it will fit under the tree when it reaches its mature size. Landscape with drought tolerant plants. Click here to see the City’s online guide to local plants.

Irrigate during the cool of the day, when the wind is not blowing. Your water will go into the ground where it is needed, and not into the air through evaporation and wind drift. The best time is in the early morning hours; just before dawn (if you have automatic sprinklers). For those who have manual sprinklers, early evening irrigation (after 5:00 p.m.) may be more practical. Watering in the late evening is risky, as it may promote plant disease such as rust; particularly during the warmer months.

Avoid hand watering when possible. With the type of soil we have, the water is unlikely to reach the roots. The best solution is to apply water slowly, over a longer period of time – just what a drip system is made for!

Heavy surface mulch should never be used in areas that are sprinkler irrigated, as it will act as a barrier; preventing water from reaching the soil. Rain will penetrate surface mulch simply because it falls over long periods of time, and in greater quantities.

Drip irrigation is a way to save a tremendous amount of water, if it is done properly. For more information, refer to the information on Drip Irrigation.

Additional Information - More information is available on solving your Telephone. water use problems. If you need to speak with someone, call the Utilities Conservation Office at 781-7217 or 781-7213.

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