Water: The essential element for all life on this planet. The Front Range of Colorado is a semi-desert climate. Rainfall averages 12” per year. Yet somehow we grow trees here, lots of trees! Supplemental irrigation is the key to our urban forest success story. The trees we plant have to watered by people. There simply is not enough natural rain and snowfall water to support the types of trees we plant.
How much water is needed then? That depends on many factors: Tree species, soil type, exposure, available soil surface area of the planting site, and ultimate size of the tree are just a few things to be considered. Know it before you try to grow it!
Let’s start with a new tree. After you have planted your new tree and have watered it in thoroughly wait a week. Before you water it again check the soil for moisture. Dig a small hole in the soil backfill next to the root ball about 6” deep. Grab a handful of soil from the bottom of the hole and feel it for moisture. If it is wet don’t water it, check the soil again in a few days, if the soil is moist, give it in another day or 2, check the soil again, if the soil is dry set the hose on top of the root ball near the trunk and let it run at a slow trickle until the soil is wet down to 8”-12”. Be sure to check the root ball itself for moisture as well.
The key here is to check the soil before you water! Watering on a set schedule may be too much or too little. More new trees die from over watering than under watering. Personally, with new trees I prefer to error on the dry side. I can always add water if it's dry. I can't remove water if there is too much!
Established trees: It takes huge amounts of water to support a large tree. When trees are planted in turf, generally they get enough water to sustain themselves if the grass is receiving proper amounts of water. However, it is suggested to test the soil for moisture, as described above, at least every 2-3 weeks to make certain the water is penetrating at least 6”-8” deep. Tree roots are located in the top 8”-12” of the soil and can grow 3-5 times beyond the drip line of the tree in search of water and nutrients. The critical zone to keep irrigated is under the drip line of the tree canopy. The drip line extends from branch tip to branch tip. This applies to trees in turf or in bed areas. Feel free to water outside the critical zone as well.
Rules of thumb for watering:
Check the soil for moisture before watering.
Water thoroughly, but infrequently.
Soak the soil down to 8-12”.
Focus your watering efforts within the critical zone, and beyond if possible.
How much water? For each inch diameter of tree trunk apply 10 gallons of water. A 10" diameter tree would need 100 gallons of water.
Trees need water year round. Don’t forget to winter water!
So far this year it has been really dry. The lack of rain this summer has extended into the fall. All your landscape plant material from trees to turf need water. I suggest using the winter holidays as a reminder to winter water.
Jones Tree & Lawn offers deep root winter watering as a service to our clients. Give us a call if we can help.
303-431-8132
email us at info@jonestreeandlawn.com
