Garden Tips: Setting the record straight on watering myths

When summer temperatures climb into the triple digits, gardeners are very mindful of watering their lawns, gardens and container plants. But there are several widespread faulty beliefs that need to be corrected to ensure that you are watering wisely.

False Belief 1: Never water your lawn or garden at night.

The caveat of not watering at night is true in warm, wet, humid areas of the country. In those regions, plants do not dry off quickly, especially during the cooler hours of the night.

This high moisture situation is conducive to numerous plant fungal and bacterial diseases. In these areas, early morning is the best time for watering.

Our local dry climate with its pervasive low relative humidity means plants dry off fairly rapidly whatever time of day or night they are watered.

Because water loss due to evaporation will be less, it is better to irrigate during the night or early in the morning when it is cooler and there is less wind.

Irrigating at night or very early morning is most efficient, but gardeners may be required to water at other times of the day because of watering restrictions when the supply is limited. If so, follow your irrigation district’s guidelines.

False Belief 2: It is normal for the leaves of some plants, like those of squash, to wilt on very hot sunny days and then recover in the evening. It does not mean that they are drought stressed.

False Belief 3: When a plant wilts, it means there is not enough soil moisture and more water is needed.

These two beliefs contradict each other, but are commonly thought to be true by many gardeners.

Both are incorrect. Wilted leaves are an indication that a plant is not getting enough water when it needs it. The plant is stressed. Inadequate root systems and excess moisture are the two main reasons a plant may wilt even when there is plenty of water available in the soil.

Underdeveloped, restricted roots or damaged roots make it impossible for a plant to absorb enough water to support the top of the plant.

If a squash transplant has pot-bound roots and they are not sufficiently loosened at planting time, the roots will not be able to grow out into the surrounding soil to access the water available there. Likewise, physical damage to the roots from deep cultivation close to the plant will impair a plant’s ability to absorb water.

When soil is compacted, roots have a difficult time developing into an adequate root system. Similarly, plants growing in containers may not have a large enough volume of soil to grow enough roots to supply the plant’s water needs.

Plants growing in wet soil may wilt despite the plentiful moisture. This is because oxygen is excluded from saturated soil.

Without oxygen, the roots are not able to function properly and are not able to absorb water. Soil compaction and poor drainage are often the underlying causes of excess soil moisture. Also, persistent wet soil conditions can lead to bacteria and fungi infecting and killing the roots, resulting in wilting and plant death.

With our summer heat and the sun beating down on our yards and gardens, it is important to water properly. If a plant wilts or shows signs of drought stress, investigate.

Before watering, check the moisture in the soil and check the roots for signs of problems.

This story was originally published July 21, 2017 at 4:41 PM with the headline "Garden Tips: Setting the record straight on watering myths."