Shrubs showing stress from lack of water. Lack of watering makes plants more susceptible to damage and disease.

Watering during the heat of the summer is mission critical to the success of your garden and plantings. The simplest rule of thumb? If your plants are looking dry, water them!

Summers in Chicagoland are often hot and humid. These are the exact conditions that disease and fungus thrive in. Watering your plants will promote a healthy plant that will be better able to fend off diseases that would take hold of a weaker plant.

It is ideal to water deep into the soil to encourage deeper roots. Deep roots will help keep the plant cooler in the summer heat as well as increase the water table available to the plants.

Newly planted plants don’t have an established root system and thus will require additional watering to help keep the plant cool, as well as encourage root growth. Watering of newly planted plants during the summer may be required each day, and if temperatures increase above 80 degrees, a second watering during the hot part of the day will also help keep the plants cool and healthy.

Let’s not forget established plants. A 35-foot tall tree transpires 30 gallons of water on a hot summer day. During a dry spell, even large trees must be watered to ensure good health and promote growth.

Watering Tips

  • Keep the foliage as dry as possible. To accomplish this, early morning watering is ideal, as less water is lost to evaporation and it will allow the soil to remain moist for a period, but give time for the foliage to dry once the sun comes up.
  • Frequent, shallow watering is not recommended as it will encourage shallow roots; shallow roots are not able to keep the plant cool during the heat of the summer and limit the amount of ground water available to the plant.
  • Be careful to not overwater; roots need oxygen, and too much water will prevent the roots from breathing.
  • Use of a rain gauge will help ensure the appropriate amount of water that is applied. For an established plant, one inch of water per week helps plants thrive and one inch of water per month is required to keep plants alive.
  • Walk on your lawn. If the leaf blades don’t bounce back, it’s dry and needs watering. Use an oscillating sprinkler for best results. Lawns will turn yellow and go dormant if stressed and not receiving enough water.
  • If you have an irrigation system, periodically check that your plants and lawn areas are receiving water. Leaf growth from surrounding plants or an added feature, such as a bird bath, can block an irrigation head’s spray path.