Keep Your Lawn and Garden Healthy in the Summer Heat

Tuesday, July 3, 2012

Help!  My lawn is bone dry!
We’re in the time of year when the sun is high and burning in the sky and we may go weeks at a time without significant rainfall.  What to do?

Continue to “mow high”, 3 inches or even more.  It’s okay not to water, and let your grass go dormant.  Grasses adapted to our area (mostly fescues) naturally go dormant in the summer; their growth times are in spring and fall.

Which also means:  don’t fertilize now.  You don’t want to force growth at a time when the grass is under stress and really wants to lie low until the worst of summer is past.  The optimum time to spruce up your lawn is from late August through October.   (Zoysia grass works on an entirely different schedule, but that’s another topic.)

If you must water now, wait until the lawn is really dry.  The grass will take on a bluish tinge and footprints will show for awhile.  Then water thoroughly  -- at least an inch.  This can take longer than you think; set out a tuna can to catch the water so that you can measure it accurately.  The worst thing you can do to your lawn now is to water it lightly and often.  The grass roots grow where the water is, and you want those roots to reach down into the ground, seeking the water.  Watering deeply and less often is the way to encourage this.

And I’m afraid my shrubs and flowers won’t survive!

Many shrubs and most trees are quite drought-tolerant once they’re established, but if you need to water them, follow the same instructions as for your lawn: wait until the soil is fairly dry a couple of inches down, and then water deeply.  Some shrubs will show their needs by wilting, but if they wilt in the sun and perk up again later in the day, this is normal for shrubs like hydrangeas and doesn’t necessarily indicate a need for artificial watering.  The ones with leathery leaves, like hollies, don’t wilt until they’re just about dead, so wilting on shrubs isn’t a useful indicator.  Check the soil several inches down.  Sticking a bamboo skewer into the soil is a useful tactic.  When you pull the skewer back out you’ll be able to tell if the soil below is damp or dry.

However, shrubs and trees that were planted this season must not be allowed to be drought-stressed.  They haven’t had time to make strong root systems, so water them regularly when the rains don’t do the job.

Annuals and perennials vary.  Impatiens always need to be damp – and they’ll show you by wilting.  On the other side, dusty miller hardly ever needs watering.   Most flowers are somewhere between these two extremes – again, once they’re established.  If you plant anything new now, keep it well watered all the time.  It will need all the help it can get.  Better yet, wait until fall to plant if at all possible, especially for permanent plants like shrubs and trees.

What about my vegetable garden?

It’s okay to let ornamentals and grasses fade a bit in order to use water more responsibly, but if you plan to eat something, you have to meet its needs.  Most vegetables should be watered from below, to avoid spreading fungus diseases on the leaves, and don’t let them dry out.  Watering in the morning is preferable, again to avoid diseases.

Next month I’ll provide some hints on getting your landscaping through the late summer doldrums.