How many INCHES of water should I give during winter watering?
CSU gave out handy blue water gauges/cups which are marked in inches and centimeters. However, the guidelines are in gallons. I have in my head 1/2" of water for the week in the summer for perennials and xeric shrubs. I leave a sprinkler on for an hour on the grass. How much water should be in my gauge when I have watered my perennial beds, pines, and xeric shrubs enough?
Another way of looking at watering and water amount is this:
an acre-inch of water (one inch of water spread over an acre; 43,560 square feet) is about 27,100 gallons.
over 1000 square feet, 623 gallons
over 10 square feet, 62 gallons equals 1 inch of water.
A standard tree watering recommendation is 10 gallons per inch diameter. So, a 2-inch tree would need 20 gallons of water applied within its dripline. Because dripline area differs with each tree, it is easier to give a recommendation in gallons (use a hose-end meter that measures water flow in in gallons). The inches of depth is more useful for watering lawns.
Hope this helps answer your questions. If not, let me know.