Determining the right amount of water for your garden is key to growing healthy plants. If you water too much, your plants will suffer from a lack of oxygen. Water too little and your plant roots will dry up. You can best help your plants by learning the signs of plant water stress and adjusting your routine as necessary.
Signs of Water Stress
There are several obvious signs of water stress. If your plant is wilting, has brown or yellow leaves, is dropping blooms or leaves prematurely or failing to yield expected fruit and vegetable harvests, chances are your plant is experiencing water stress. Many gardeners make the mistake of overwatering, which saturates the soil, diminishing a plant's access to necessary oxygen; you can, in essence, drown your plants. But if you do not water enough, your plant's roots can dry out. They will then try to pull moisture from the rest of the plant, resulting in severe dehydration.
You don't need much more than your finger to test whether your garden needs water. Stick your pointer finger into the soil. If the soil feels moist all the way to the first knuckle, you likely don't need to water. If the soil feels dry, it's time to water. You can also purchase soil moisture sensors or probes. Do not rely on the soil surface to indicate the moisture level. Soil surfaces will be the first to dry out, but the deeper soil may be perfectly moist.
The basic rule of watering is to water deeply, but not often. Established plants need less water on a frequent basis. Rather, they tend to do better with a deep watering (at least 1 inch) once a week or less. For potted plants, use the finger method. It is important to not overwater potted plants; they already have limited room to balance their oxygen and water needs. But they also dry out more frequently than any other part of the garden. Most potted plants need to be watered every third day or so during the hottest months.
Overhead sprinklers and watering cans are effective methods of watering, but soaker hoses and drip irrigation both sit on the soil and provide the deep watering most beneficial to plants. Use a timer to help you remember to shut off water. Most plants benefit from one to two hours of irrigation watering at a time.
It is also helpful to consider the type of soil you're planting in. Clay provides little room for root growth and does not drain well. Sandy soils drain water quickly. Help your plant maintain a healthy moisture level by helping your soil. Adding mulch to clay or sandy soil will increase their capacity to hold moisture without becoming saturated. You can also add mulch around the base of individual plants to help with moisture retention.
Know your planting zone. Some plants are not meant for hot, dry climates, while others are not suited for cooler or coastal regions. Select plants based on their ability to grow well in your area. When buying new plants, read tag descriptions, which often note which area of the country the plant is best grown in, and whether it prefers full sun or partial shade.
Mornings are the best time to water plants so plant roots can take advantage of the moisture as the day warms.. Do not panic if a particular plant looks slightly wilted in the middle of the day. Plants naturally droop during the hottest hours, but bounce back once it cools. Water in the late afternoon only if you know leaves will be able to dry before nightfall. Wet leaves and cool temperatures result in fungus growth and other diseases.
Writing a watering schedule can also help. It can be as simple as marking on a calendar when you water or a more complicated schedule that records what was watered, for how long and when the next expected watering day is. A schedule will help keep you from overreacting to a dry soil surface or a plant that appears wilted in the afternoon sun.