Summertime weather conditions are arriving soon as the temperature steadily climbs a few degrees every day or two. Unfortunately, it looks like we’ll be going into summer on the dry side. That means we will need to water our landscape and gardens to minimize drought stress and keep our plants alive and healthy.
Of course, using more irrigation water means our water bills will dramatically increase. And increased usage can put a strain on some community’s water resources and ability to deliver water to maintain critical infrastructure functions during prolonged droughts. So, it makes sense to use this most precious resource wisely and efficiently.
Knowing when to water and for how long is fundamental to maintaining a quality landscape that is also water efficient. Newly planted trees and shrubs need more frequent watering from the time they are planted until they are well-rooted. During this establishment period, plants can be gradually weaned to a less-frequent watering. Proper weaning develops deep roots and makes plants “drought enduring.”
Of the tremendous amounts of water applied to lawns and gardens, much of it is never absorbed by the plants and put to use. Some water is lost to runoff by being applied faster than the soil can absorb it, and some water evaporates from exposed, unmulched soil before it can be used by the plant. But the greatest waste of water is when too much is applied too often.
Many lawns receive twice as much water as they require for a healthy appearance. It is best to not water by the calendar. Rather, it is better to water when the plants need watering. Most gardeners can readily recognize lawn stress signs due to lack of water, such as wilting and going “off color.” The key to watering lawns is to apply the water as infrequently as possible, yet thoroughly so the soil is wetted at least 5 or 6 inches deep.
Like lawns, trees and shrubs should be watered as infrequently as possible, yet thoroughly. Most established trees and shrubs will benefit from a twice-a-month thorough watering during the growing season in the absence of adequate rain. Normal lawn watering is no substitute for thorough tree and shrub watering.
There are two main types of irrigation systems used in gardens — sprinkler and drip. With an Earth-Kind landscape, it is recommended to use a combination of both systems in watering turfgrass, trees, shrubs, ground covers, flowers and vegetable gardens.
Sprinkler irrigation is the most commonly used method of watering. The two kinds of sprinkler irrigation systems are the hose-end sprinkler and the permanent underground system with raised sprinkler heads.
The differences in these two sprinkler systems are in the cost, convenience and efficiency. Permanent, sprinkler systems are much more expensive than hose-end sprinklers. Yet the permanent system is much more convenient and can be much more efficient in applying water when properly designed. The major advantage for sprinkler irrigation is in lawn watering.
However, there are some potential drawbacks to sprinkler irrigation for shrubs and flowers. Sprinklers wet the plants, as well as the soil. Water which remains on a plant through the night increases disease susceptibility. Therefore, sprinkler irrigation should be used early in the day to allow time for the plant leaves to dry before nightfall.
Another disadvantage of sprinkler irrigation occurs on windy days. Watering in as little as a 5 mph wind will distribute the water unevenly over the area and result in a great deal of evaporation. In beds with shrubs and perennials of varying heights, water from sprinklers is often deflected as plants grow taller and fuller, leaving dry spots where the water is not evenly distributed.
The most efficient way to water the home landscape and vegetable garden is with a properly designed and well-maintained drip irrigation system. Drip irrigation slowly applies water to soil, flowing under low pressure through emitters laid alongside the plants.
Water applied by drip irrigation has little chance of waste through evaporation or runoff. The water is applied directly to the plant’s root zone. This also eliminates waste from applying water to unplanted or weedy areas.
Irrigation requirements vary according to plant species, soil type, rainfall, and temperature. Established, well-adapted plants require less frequent watering than newly planted trees and shrubs. Annuals and vegetables will need more frequent irrigation than perennials and shrubs. Cover the drip system with mulch to hide the tubing from view and add to the life expectancy of the system.
There are many drip irrigation products on the market. All are basically good, and there is no great advantage of one over another, but regardless of how good the products are, they all eventually stop up. Drip systems must be maintained and cared for, as with other water systems; hence, it is best to leave the emitter and loops on top of the ground so they can be checked regularly. The most practical applications for drip irrigation in the home landscape are in gardens, hedge rows, shrub or flower beds, and combinations of these along with trees.
When properly utilized, irrigation systems give plants a sufficient amount of water without waste. Ideally, planting areas with a higher water requirement can be watered separately from lower-water-use plants by grouping plants by like water needs and zoning the irrigation systems accordingly.
On Saturday, May 17, the East Texas Garden Lecture Series focuses on drip irrigation for the home garden.
Brad McCullough, manager of Ewing Irrigation of Tyler, will discuss home watering in general, reasons for using drip irrigation, different types of drip irrigation products, how to figure water requirements for flower beds and gardens, and the components needed for a drip system. That will be followed by a demonstration in the IDEA Garden on how to retrofit and convert an existing sprinkler system from spray heads to drip. There will be plenty of opportunities to ask your irrigation questions.
Registration is open at 8:30 a.m. at the Tyler Rose Garden Center, and the program begins at 9 a.m. Cost is $15.
Keith Hansen is Smith County horticulturist with the Texas A&M AgriLife Extension Service. His web page is http://EastTexasGardening.tamu.edu. His blog is http://agrilife.org/etg.