How Do I Know If My Trees Need Water in the Fall?
Turning off the sprinkler system does not necessarily mean your trees are done needing water.
Colorado Springs can move from warm autumn afternoons to freezing nights quickly, and our fall weather is often dry. Trees do not stop needing soil moisture just because the irrigation system has been winterized.
CSU Extension recommends supplemental watering during prolonged dry fall and winter periods, especially for newly planted trees, evergreens, and plants growing in exposed or sunny locations.
Start with the soil, not the calendar
Check several inches into the soil in the tree's root zone. If it is cool and reasonably moist, there may be no need to add water. If the soil is dry and crumbly after an extended period without meaningful rain or snow, supplemental watering can be worthwhile.
South- and west-facing areas, windy sites, shallow soils, and places that receive reflected heat from pavement or walls can dry substantially faster than protected areas.
Choose the right day
CSU's fall and winter guidance is to water when air and soil temperatures are above 40°F, the ground is not frozen, and there is no snow cover. Water early enough in the day that it can soak into the soil before temperatures fall at night.
Water the roots, not the trunk
A mature tree's useful root area is much larger than the small circle immediately around the trunk. Apply water slowly across the root zone, concentrating within and around the drip line instead of dumping water at the base of the trunk.
Newly planted trees deserve extra attention because their root systems still occupy a relatively small volume of soil and cannot reach distant moisture reserves.
Sources & further reading
These Field Notes translate Colorado horticultural guidance into practical homeowner language. For the underlying recommendations, start with the original CSU Extension resources: