Before adding irrigation to landscaping, make sure it’s needed. Appearances can be misleading, and cause water to be used unnecessarily.
First, use “digital” technology. Because soil may appear dry on the surface, stick your finger into the soil and see if the soil is wet beneath the surface. If the soil is moist up to your second knuckle, it doesn’t need any more water. Wait for another 24 to 48 hours, and check the soil again.
As an alternative, use a soil probe and measure the moisture in the soil to determine whether the soil needs more water.
Another strategy is to assess plant health. How vibrant are they? This can be tricky, because sometimes the signs of overwatering and underwatering will produce similar results in plants.
Underwatering symptoms include:
- Soil is bone dry
- Older leaves turn yellow or brown, and drop off
- Leaves are wilted
- Leaves curl and become brittle
- Stunted plant growth
Overwatering symptoms include:
- Soil is constantly saturated and soggy
- Leaves turn a lighter shade of green, or turn yellow
- Younger plant shoots wilt
- Leaves are green and brittle
- Algae and mushrooms are in the soil
- Growth is excessive
Since the symptoms at both extremes can be similar, it’s best to rely on objective measurements rather than observations. Using simple measurement tools can help ensure the correct amount of irrigation takes place without withholding needed moisture, but without overwatering and wasting resources.
This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.