Water is a finite commodity, and it is important to use it judiciously to make sure there is enough to go around. Some plants need supplemental watering in some situations. Other plants have built in mechanisms to help them survive temporary dry conditions and then allow them to be rejuvenated when the rains start in again. Knowing when and how to water will help you keep your plants healthy and not waste water.
Healthy plants are important for a variety of reasons. Not only are they beautiful to look at, they provide numerous environmental benefits. Lawns filter rain-water and release moisture back into the air. This natural process cools the grass and the area around it, much like perspiration cools our bodies. The air around a lawn can be as much at 30 degrees cooler than that over driveways, sidewalks and other paved areas.
Once a lawn becomes established it can usually survive very well with whatever water nature supplies. Yes, a lawn with cool-season grasses (bluegrass, fescues and ryegrasses) may turn partially to totally brown in the heat of the summer. This is similar to warm season grasses (Bermuda, Zoysia and St. Augustine) turning brown with a frost and cold weather.
If you have the right kinds of grass for your area, it will green-up again when the weather is right. The cool-season grasses green-up with autumn rains, and the warm-season grasses with warm spring and summer temperatures. Even under extreme droughts, lawns can come back if they have proper prior care such as regular fertilization, and de-thatching and aerating as needed. Because fertilizers need moisture to become activated, and some pest controls need watering-in after application to activate them, keep an eye on the weather time your application to coincide with predicted rain and let that water it in.
Most ornamental plants that are meant to grow in your area will also grow quite well with whatever moisture nature supplies. Keep this in mind as you plan your plantings and use those plants that are best suited to your area. If you have some valuable plants that need extra water and rains are sparse, it is best to water early in the morning. There are two reasons for this. First, the plant will have the water available during the heat of the day so it will dry out much less quickly. Secondly, disease pressures can be kept at a minimum if the leaves are not wet as the evening cools off.
You may have to decide which of your plants are the most valuable and which you can let go if necessary. Once you determine which plants are the most valuable, only provide water as needed for survival and not so much that a flush in growth occurs. You can talk with your local county extension agent or a Master Gardener for assistance in making those determinations. Let them know what plants you have and whether they are in sun or shade.
For container plants, morning watering is also preferred. Use a soil in your containers that retains water well. A little mulch on the top of the soil can also help in water retention. Water just to the point of saturation, but don’t over-water.