Water-Wise Food Gardening Sonoma County - University of California

Water-Wise Food Gardening Sonoma County - University of California

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  WATER-WISE FOOD GARDENING WhyConserve? Sonoma County has a Mediterranean climate. Almost all of our rain falls from November through April and usually there is no rain at all during the summer months. Our water supply is limited to groundwater and to surface water flows from the Russian River/Lake Sonoma system, both of which have been decreasing in recent years. Water conservation is crucial. The main rule of summer watering is to try to use and waste as little water as possible while still keeping your food garden productive. The most useful techniques for water-wise gardening are good soil preparation, drip irrigation and mulching. Soil Preparation the plants. Usually a filter and pressure regulator are installed at the garden faucet to which the drip Soil that is loosened deeply with generous system is attached. amounts of organic material (eg. compost) mixed into it stores much more water than compacted Options for delivering water to the plants include soil. Plant roots will grow deeper and be protected the following: from the summer sun, and the garden will need • Porous soaker hose which oozes along the less water. An added bonus is that soil in good entire length – these attach to garden hoses condition holds nutrients better and drains well in and are inexpensive. Use only with city the winter, making water-logging and root rotting water. less of a problem. • Tubing with in-line emitters – this comes in ½-inch width with emitters every 12 inches Containers used for growing food plants must be and ¼-inch width with emitter spacing of 6 or large enough for healthy root systems so plants 12 inches. These work very well in food can be productive. In large containers such as a gardens and last a long time. planter box or half wine-barrel, a mixture of about 1/3 amended topsoil and 2/3 good quality organic • Micro sprinklers – good for watering seeds potting soil will give the best results. In smaller beds, and for watering under fruit trees and containers use just the potting soil and refresh at cane berries, these come in a wide variety of least a quarter of the soil mix each year. spray patterns and flow rates. • T-tape – used for larger vegetable gardens, Drip Irrigation these inexpensive plastic lines are laid out along rows and drip from in-line emitters. Drip irrigation uses water efficiently. Unlike Ground must be fairly level to work well and sprinklers and hoses, drip irrigation brings water rows must be straight. directly to plant roots without losing it to evaporation or runoff. Drip provides precise water Water quality and pressure must be considered control, increases yields, results in fewer weeds, when laying out a drip system. Local irrigation saves time and labor, keeps leaves and fruit dry supply houses are happy to assist with system reducing disease problems, promotes better soil design and starter kits are available at hardware structure, conserves energy, and can use low stores. Another great resource for information on water pressure. drip irrigation is Drip Irrigation for Every Landscape and All Climates by Robert Kourik, a long-time Components of a standard drip system include a Sonoma County gardening expert. length of ½-inch tubing that brings water from a pipe or garden hose and feeds the tubes going to
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  Any irrigation systemshould have the lines increased during these times. Your garden checked and flushed yearly, or more often if water loses moisture both from the soil and the quality is poor. The lines will last much longer if plant’s leaves, so large plants can pull a lot they are protected from the sun by mulches, (see of water out of the ground on a hot day. below). Remember to reduce watering during cooler periods and when days shorten in When to Water for How Long? the fall. It is often better to decrease The most active feeding roots of most plants are in watering time than frequency. the top 1 to 2 feet of soil, so this area is the most important to keep moist. Although they ultimately Mulches save water, drip systems need to be run more Mulch is material that is used to cover the ground frequently to keep soil moisture levels ideal. Roots around plants in order to discourage weeds and to need air and will die in water-logged soils, so over keep the soil from drying out. It is most useful in watering is bad for plants as well as a waste of the summer since it cuts down substantially on water. However, if only the soil surface is kept water use. Some mulches can make it difficult for moist, roots will stay very shallow, dry out quickly water from sprinklers or a hand-held hose to and the plant cannot reach full potential. percolate down into the soil – but mulching works perfectly with drip irrigation when mulch material is The amount of water applied should equal the added over the tubing. amount of water lost. How fast water is lost depends on several factors, including: Mulch is also valuable in the winter to help protect • Soil type: Sandy and silty soils dry out roots from frost and soil from erosion and more quickly and water moves through compaction, but it can prevent soil from warming in much faster than clay soils. This means the spring. Mulch can also be home to slugs, drip lines and/or emitters must be spaced snails, and earwigs, so it should not be applied more closely and can be turned on more until plants are well established. frequently for short times. Clay soils hold water much longer and water will spread • Vegetable Beds: Organic mulches, such as horizontally much farther, though it can take straw, alfalfa hay or old leaves, and/or aged a long time to do so. Drip lines in clay soils manure with bedding or rough compost, are should have low output and be turned on preferred for vegetable beds as they will longer. slowly decompose and enrich the soil. • Containers: These tend to dry out much • Paths and Trees: Wood chips and sawdust faster than the ground and may need should not be used in vegetable beds but are watering every day during hot weather. fine for paths and for covering a layer of • Plant needs change with age: Young compost around fruit trees and other plants have small root systems so the soil perennials. Always leave an unmulched ring surface must be kept more moist than for of space right around the base of perennial mature plants. In addition, some plants plants, trees, and shrubs. such as lettuce, broccoli, radishes and • "Sheet mulching" involves layering onions are shallow rooted, whereas materials over a lawn, moist bare soil or tomatoes, squash, and melons can grow mowed annual weeds, starting with compost deep roots and draw moisture from a large or manure, then cardboard or newspapers, area. and topping with tree trimming chips or straw. • Mulch: A protective layer of material on This technique provides added weed the soil surface will shade the soil and suppression, can be used around trees or in reduce evaporation. Mulched areas will paths and is an excellent way to improve the need watering less frequently. (See below soil in a new area where you want to plant for more information.) edibles in the future. See the iGrow • Weather: Heat and wind are very document, "How to convert your lawn to a dehydrating so irrigation may need to be garden". www.igrowsonoma.org 2 By: Suzanne Doyle, Robert Kourik and Wendy Krupnick, 2009