University of Vermont Extension 
Department of Plant and Soil Science

Summer News Article

Charlie Nardozzi, Senior Horticulturist
National Gardening Association, and
Dr. Leonard Perry, Extension Professor
University of Vermont

Fertilizing blueberries, proper watering, and proper mowing are some of the garden tips for this month.

Blueberries benefit from an acidic fertilizer each year. Apply one half pound of ammonium sulfate when the bushes start blooming, and another half pound four to six weeks later. If the leaves turn yellow with green veins, they may have an iron deficiency. Applying two to three ounces of ferrous sulfate or iron chelate around the base of the plants will help correct this.

The best time to water the garden with a sprinkler is in the morning, second-best is late afternoon, worst is during the hottest part of the day. So much water is lost when using an overhead sprinkler on a sunny afternoon that you may as well pour it down the drain. Even better than a sprinkler are drip irrigation systems and soaker hoses, which slowly apply water directly to the soil and don't wet the foliage. If you do use a sprinkler, be sure to keep it on long enough to wet the soil to the root zones. This can take much longer than you think.

Frequent rains leach fertilizer from the soil of container plantings, so they need to be fertilized more often than plants in the ground. Mix liquid fertilizer into the watering can and use
it weekly. Don't fertilize when the soil is very dry or it can burn the roots, so you may need to water plants first, then water with the fertilizer solution.

Raise your mower blade to cut at three inches to allow the grass to better withstand the heat. If you cut too low, the grass will rapidly turn brown. Keeping the grass longer also will help shade any weed seeds and reduce their germination.

Catmint, veronica, salvia, and some other low-growing perennials will give rise to another flush of blooms if the flower stems are sheared just below the old flowers. The lower down on the stem you cut, the longer they will take to rebloom.

As soon as you spy the telltale black spot ringed in yellow on your rose leaves, it's worth trying this home remedy: mix two tablespoons baking soda plus two tablespoons liquid soap into four quarts of water. Coat the leaves with the spray, and reapply after heavy rain.

Woody plants that you put in this spring or summer need adequate watering for the first year. Even when it rains, the moisture might not soak deeply enough to reach the roots and encourage them to spread. The best way to apply water is to lay your hose at the base of the plant and let it drip for an hour or more. Then gently dig down to see how deep and far the water penetrated. You'll probably need to move the hose several times to reach all around under the tree. A soaker hose makes this easy because you can lay it in a ring around the plant to water all sides evenly.

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