Water wisdom


All living things need it to survive.  We drink it, we bathe in it, we swim in it, and we fish in it. We often take it for granted. In Arkansas we are blessed with an abundant supply of water, yet we still need to use it wisely. To keep your gardens happy and healthy, make sure you know how and when to water.

Water is the main ingredient for gardening success or failure. While there are guidelines on how to water, the same rules don’t apply to all yards. Different plants, different soils, sun versus shade, and the type of system you use will all make a difference. Learn what your specific yard and plants need.

The basic rule of watering is to keep your plants healthy with the least amount of water possible. As a general rule, plants need 1 to 1 ½ inches of water per week during the growing season. When the weather gets really hot and dry, we may bump that up to 2 to 2 ½ inches of water per week. An easy way to measure water output is to use small cans or jars placed in a random pattern under your sprinkler. Turn on the sprinkler and time it for 15 minutes, then measure how much water is in each of the jars. Get an average of how much water is being put out every 15 minutes. If you have collected 1/4 inch of water, you then know you are applying an inch of water per hour.

The slope of the yard will also be a factor. You want the water to get into the ground not the sewer system, and you want to keep your plants alive, not drown them. If you live on a level lot, and you have good soil, then you can set the timer and let it go, but if you have rocky soil, or live on a slope, then pay attention to how soon the water begins to run off. Once water begins to run, stop the sprinkler cycle and move on to the next zone.

Different sprinkler heads put out different amounts of water. If you are watering with a hose-end sprinkler, water in shorter cycles, allowing the water to penetrate before adding more water.

Watering needs vary throughout the season. Infrequent but deep watering is better for your plants. It helps plants form a deeper root system, which will tolerate extremes in temperatures and drier conditions more easily. Daily, shallow watering encourages shallow roots, which make your plants even more dependent on water. Potting soil tends to dry out much faster than garden soil, and raised containers dry out faster than plants in the ground.  Mulching will also help conserve moisture.

Depending on your soil conditions and what you are growing, some gardeners may have to water every day or two in the summer, and get by with once every week or two in the spring and fall. Never set an automatic system to operate year-round the same way. Be sure to test each zone of your system. If your system is set to go on from 3:30 to 5:30 a.m., you probably aren’t awake to make sure things are operating smoothly. Run the system at least once a month when you are up and have time to monitor it.

Drip irrigation systems are the most efficient to use and are readily available. They direct water to the root zone of the plant, keep the foliage dry and have little water loss during application. To know how much water they are putting out, simply collect water from several of the individual emitters and time it like you would for an open spray system. Then set each zone individually to get the amount of water needed.

Early morning is the ideal time to water, since there is less wind activity, the temperatures tend to be a bit lower and the water gets into the root zone before the plant gets stressed by the heat of the day. Early sunlight will help to dry the plants’ surface more quickly and can reduce the incidence of diseases. Sometimes personal schedules don’t allow for early morning watering, so water when it is convenient for you — the goal is to keep your plants living and try to make sure foliage dries before the sun sets to reduce foliage diseases.

Regardless of how often you water, the key is to know what your plants need to thrive. Some plants are more drought-tolerant than others, and not all areas of the yard have the same water needs. Soil type, amount of sunlight, what plants you are growing — lawns versus flowers versus vegetables — will all have an impact. Native plants that are blooming along roadsides are a great indicator that they don’t need a lot of extra water to survive. Try to group plants together based on their watering needs. Check for signs of water stress: wilted leaves on flowers or shrubs. Lawns will take on a bluish cast, have curled foliage or leave behind your footprints when you walk across it. Vegetables won’t produce well if they get too stressed.

Finally, invest in a rain gauge. They aren’t expensive, and you need to know how much rainfall your yard gets, not what is reported on the news.  And remember: don’t water unless you need to.

Janet B. Carson is an extension horticulture specialist for the University of Arkansas Cooperative Extension Service.