Apply Fertilizer to Trees When it Cools Off

Q. How much fertilizer should I give my trees in the landscape and when can I do it?

A. Apply fertilizer to established, winter hardy landscape trees late in the season when temperatures have cooled down, trees aren’t growing anymore but they still have leaves. This is called a late fall fertilizer application and substitutes for a spring fertilizer application. In the Las Vegas Valley this would be around late October to the middle of November.

            Apply it to the soil after an irrigation by using a sharpened, round nosed shovel. Push the shovel into the ground as deep as you can and push it forward. Drop a half cup of this fertilizer in the slit made by the shovel and close the slit with your foot.

            If the trees canopy is 10 foot in diameter, use two half cups of fertilizer, one on each side of the tree, 2 feet from the trunk. If the trees canopy is 20 feet in diameter, use six each, half cups of fertilizer, three on each side and spaced about 2 feet apart. If the trees spread is 40 feet in diameter, apply 24 of these half cups in wet soil under the canopy. Turn on the irrigation water in a normal irrigation cycle, let it dissolve the fertilizer in the soil and carry it to the roots.