Communities are using watering bags to save time and labor.

These communities have turned to this technology to reduce their labor costs while at the same time effectively irrigating trees.

The typical watering bag is made of polyethylene and holds 15–20 gallons of water. The pouch is wrapped around the outside of the trunk and its sides are zipped together. The trunk does not get wet.

Once filled, water will ooze out of holes in the bottom of the bag for 5 to 9 hours. The trees are watered deeply, helping to develop deep root systems. 

There is an old rule that a newly planted tree needs a weekly application of 10 gallons of water per inch of trunk caliper (its diameter measured 6 inches above the soil line). Thus, a tree with a caliper of 1–2 inches needs 10–20 gallons and will benefit from a once-a-week watering using the bag. Larger trees (2–3 inch caliper) can be irrigated twice a week. Trees up to 8 inches can be irrigated using a double bag setup. 

Bags can be easily unzipped so you can move them from tree to tree.

The bags are made by several manufacturers and cost about $25 each. They can be purchased online or through landscape supply stores.

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. Published in the NDSU Yard & Garden Report, August 1, 2017. Photos were made available under Creative Commons licenses specified by the photographers: Angela de Março and Heartlover1717.