Watering is the most basic and necessary task of gardeners everywhere. With water resources becoming more and more scarce in many regions, it is important to know how to give our gardens a drink with as little waste as possible. Being thrifty with water not only makes us environmentally responsible, but it is better for our gardens as well, since overwatering our gardens can sometimes result in killing our plants with kindness! “Water-wise” gardening results from knowledge of both our individual properties and the regions in which we live. Cyclical weather patterns—in particular, the average annual temperature, and the amount of annual precipitation and when it falls—tend to dictate when, where, what, and how much we can grow in any particular region. Knowing the type of soil in our gardens is also important. Generally speaking, there are three types of soil: clay, sandy, and loamy. Typically, the “heavier” the soil (meaning the more water-binding clay particles it contains), the longer it will hold water. Most plants require well-drained soil, so heavy soils will need to be amended. At the other extreme, water drains quickly through sandy soils. Sandy soils also should be amended to help with water retention. There is a simple method for testing the drainage of your soil. Dig a hole 12 inches deep and fill it with water. A good rate of drainage is about one inch per hour. So the water in your hole should completely dissipate in 12 hours at the most. If it has not drained within 12 hours, then you probably have clay soil. You can also give your soil a quick squeeze test. Pick up a clump of soil and gently squeeze it in your hand. If it retains its form and doesn’t budge at all, it has clay properties. If it falls apart as soon as you open your hand, it’s probably sandy soil. If it retains its form but crumbles when you poke at it, you’ve got good loamy soil. Amending soil can be as simple as mixing in organic matter. Adding organic matter such as compost, peat moss, pine bark, or well-rotted manure can alter the water-retaining capacity of any soil, making it more “loamy” and providing a more hospitable environment for plant roots. Good soil is an essential first step to providing proper irrigation to your gardens. The amount of sunlight a garden area receives also affects watering needs, but it is not necessarily true that the sunnier parts of a garden will need more water. Plants adapted to grow in full sun (which may be native to prairie or desert areas) can also be more drought tolerant, using water-storing leaves and stems or deep root systems to survive long stretches of dry weather. A plant that wilts in the midday heat is not necessarily thirsty. Wilting in hot weather is one way that plants conserve water—but it can also mean that this particular plant needs to be moved into a shadier spot, or is perhaps not adapted to your hot climate and needs to be replaced.
Watering methods There are many irrigation methods used by gardeners across the country. The most inefficient is the use of overhead sprinklers. When used on a sunny day, most of the water is lost to evaporation. Sprinklers are difficult to direct (often watering the sidewalk and adjacent street) and, when used in conjunction with automatic timers, do not take into account the actual weather, coming on even during rainstorms. Soaker hoses and drip irrigation systems provide water directly to the soil and, if carefully designed around existing plants, directly to the root zones of individual plants. A key component of these systems is some kind of pressure regulation. Without this, the section of piping closest to the faucet will receive a flood of water, leaving barely a trickle at the end of the line. These systems can often be buried under a layer of organic mulch, increasing their efficiency. In any area of the garden, with or without irrigation, such mulches help conserve soil moisture and keep soil temperatures cooler in hot weather. Watering a garden by hand, with either a hose or can, can be one of the most soothing and satisfying gardening tasks, providing an intimate connection with the fruits and flowers of your efforts. It also gives you the opportunity to inspect your plants closely for pests. Deep watering once a week, which encourages the roots to go deep in search of water, is far better for plants than lightly spraying them more often, which keeps roots on the surface and will result in more frequent wilting and stress in hot weather. A good quality hose will have brass connectors, be made predominantly of rubber (rather than vinyl) in six to eight layers, or plies. The best hoses are often described as “no-kink”, and come with lifetime guarantees. A 5/8-inch diameter hose will deliver more water than the half-inch, which can be important if your household water pressure is low or you are connecting several hoses for a run of 100 feet or more. Hose accessories are many and varied; among the most useful are quick-connectors which can be used to snap the hose into the faucet or a sprayer, or hose sections into each other. The best of these are brass “full bore”, which will maintain pressure by allowing full flow of water from one hose section to the next. The best watering cans are well-balanced and have two handles, one on top and one on back, which make them easier to tip and pour with precision. A “rose” that fits onto the end of the spout can create a fine spray where desired; a can with a removable rose is more versatile than one where the rose is permanently attached. Choose a can of a size that matches your physical strength—an empty can weighs little compared to the water you’ll be lugging, which weighs 8.33 pounds per gallon. Watering newly planted trees in their first several seasons is crucial to their long-term health. Tree-watering bags, which hold 20 gallons or more and wrap around the tree trunk, allow water to seep from the bag slowly and prevent runoff. An alternative is to put a trickling hose at the tree’s root zone, and leave it for several hours. The key is to give the tree enough water to equal an inch of rainfall per week.
For more information Local garden clubs, plant societies, master gardening programs, public gardens and arboreta, and local nurseries are great sources for information and inspiration. In the U.S., most county cooperative extension offices have horticultural experts on staff with extensive knowledge of their particular region. To find your local office, visit https://www.usda.gov/ or check the Blue Pages in your phone book. Endless information is also available through the Internet. The best and most accurate web pages are often posted by the institutions mentioned above. Remember—gardening is simply playing in the dirt with a purpose. So go out there and have fun!