By: Julie Barnes
Watering plants properly is strategic to gardening especially during hot, dry weather. How often you water can be governed by weather, soil, or even the plant's needs. Yet, whenever you do water, it is best to do so thoroughly. A strong liberal soaking triggers a plant's roots to search deeper for water while a light watering encourages the roots to remain closer to the soil surface where it must be done quite frequently. When watering, the aim is to direct water straight down into the root zone. This may take two to three times longer than you think and knowing whether it is enough is not always evident by a moist soil surface. It is important to know when to water and to do so only when it is necessary.
Plant cells are mostly made up of water and when these cells are full stems stay upright and leaves expand to receive sunlight. Since water makes nutrients available through the plant's roots, it becomes difficult for a plant to absorb them when soil becomes too dry, resulting in reduced flowering, leaf drop, increased pest problems, or even death. Water must penetrate the soil at least six to eight inches for plants started in the ground to be watered efficiently. A way to determine whether your garden is being watered enough is to take a trowel and dig a six inch hole after watering and then scrape soil from its bottom. If it enough is to take a trowel and dig a six inch hole after watering and then scrape soil from its bottom. If it feels damp then your garden is receiving sufficient water. An easier way is to use your finger as a guide by poking it down into the soil. If it feels dry a couple of inches down then more water will be needed. Again, this cannot be determined by just touching a damp soil surface which often dries out very quickly.
The best time to water is early in the morning when the temperature is cooler and less water will be lost to evaporation. As the temperature steadily begins to rise plants will easily absorb the water. Early morning watering is also best for plants susceptible to fungal diseases, such as roses, because it enables their leaves to dry more rapidly. The second best time for watering is late afternoon but, here wetting the plant's leaves should be avoided because the cooler evening air may encourage fungal growth when the leaves do not have a chance to dry. The traditional rule of thumb is that plants need an average of one inch of water per week. Whenever there is no rain, this must be provided by the gardener. Generally, during hot extendedly, dry periods, established plants may need to be thoroughly irrigated once a week.
New plantings, along with bedding plants and vegetables may need to be watered at least two to three times a week to thrive under the same conditions. Watering should NOT be done automatically each day except for plants growing in containers. Because their roots grow in a limited amount of soil, they easily dry out during hot, dry weather weeding habitually watered every day. Just know, too, that overwatering can be just as bad as, or even worse, than under watering which can lead to a lack of oxygen and even rotting of plant roots. Most water lost from landscape plantings is due to evaporation from the soil which can be slowed down by the use of mulch. Mulch conserves water and maintains coolness in the upper layer of soil. Growing drought tolerant plants may help save watering time as well. If you water properly to obtain deeper rooted landscape plants, they should tolerate hot, dry weather without your constant unwavering attention.