In South Texas, we can go for weeks, or even months, without a single good rain. To survive, your plants depend entirely upon you for their water, and it helps to know how much and how often to water your garden.
The water needs of a garden can vary greatly in the extreme weather conditions of South Texas. The key to knowing when to water is to check the soil.
Ideally, the top five or six inches of soil should remain moist at all times. This top layer of soil is where most of the healthy bacteria and micro-organisms live, and they require even moisture to thrive.
The garden dries out from the top layer of soil on down. Use your finger to dig into the garden bed to check the amount and depth of moisture around the plants (see pictures below).
When it is time, water the soil slightly deeper than the lowest level of the roots. Watering past this point is simply wasting water. Let the soil mostly, but not completely, dry out, before watering again. This deep and infrequent watering promotes vigorous root growth by forcing the roots to reach into the soil seeking water.
It is best to water the soil, not the plants. In fact, most plants, like tomatoes, don’t like water on their leaves, which causes the leaves to turn yellow and wilt. Use the rain setting of your garden hose to drench the soil at the base of your plants, but not the plants themselves.
If possible, water the garden in the evening. Plants do a lot of their growing at night, and they need plenty of moisture in the soil to optimize their nighttime cellular functions. If you water during the morning, or even worse, at mid-day, you will lose a lot of water to evaporation and leave the soil dry during the night.
To prevent the soil from quickly drying out, add a thick, insulating layer of native leaf mulch around your plants. A thick layer of native leaf mulch can reduce the water needs of your garden by up to fifty percent.
As you dig into the soil to check the level of moisture, carefully observe the plants in your garden. You will quickly see the relationship between the health and appearance of your plants and the level of moisture in the soil. Your soil will tell you exactly how much, and how often, to water your garden.