I FEEL ABOUT MY GARDEN like I feel about a lot of things these days: cautiously optimistic. After weeks of fine blue skies and dry, hot days, we’ve had 0.8” of rain. I’m grateful, but I’m not hanging up the hose just yet, as its not nearly enough to make up the deficit. Yet rain sometimes begets rain, so I’ll cross my normally green thumbs, (now a bit wilted), and envision that the toasty trend will be reversed.
After the recent sprinkles, I wonder if the plants have a sense of hope, too. The daylily leaves have turned a pallid shade of green, while the hostas are seeing their leaves shrivel, one by one. Kentucky bluegrass lawns are gray-green to brown, while weedy crabgrass remains a vibrant shade of lime. My potted maroon elephant ear sulks when its bottom saucer dries daily. The growth of wood sorrel, chamomile and spurge in the gravel driveway has slowed to a crawl, and few new weeds have germinated. And our big black walnut tree has started dropping yellow leaflets. I’m sure the roots go down to China, so soil moisture must be part of the trade war.
A gardener’s response to weeks of drought plus a heat wave is to water. But are we watering wisely? One deep watering, rather than several shallow sprinkles, will encourage deeper rooting. Watering in the morning is best, since it allows plant foliage to dry as the sun intensifies, which reduces the potential for foliar diseases. And putting water low to the ground, rather than spraying the entire plant as if it were a dog in need of a bath, is more efficient from a water conservation standpoint. At a friend’s peony garden, the automatic sprinklers come on every day for a few minutes at 5:30 p.m., violating all three rules. The result is a white bloom of ugly powdery mildew spreading through the peony patch.
Science, of course, can quantify the situation. According the U.S. Drought monitor, eastern-most New York and is in “moderate drought,” the second of five progressively drier and scarier categories. TV meteorologists are telling us we are about 5” short of precipitation for the year, and local communities with public water systems are starting to implement conservation measures.
Cornell meteorologist Art DeGaetano of the Northeast Regional Climate Center reported on June 25 that during the previous week, evapotranspiration (ET) was very high at 1.25 to 1.5 inches. While some may remember ET as the bike-riding extra-terrestrial, Art’s ET is the amount of water lost by a plant as it transpires, plus the amount of water lost from the soil as it dries. For the plant’s sake, an amount of water equal to the weekly ET should fall, either from rain or irrigation, to keep things growing. But when we have high heat, intense sun and no rain, ET soars and plants suffer.
Here’s my hidden agenda. I’m hoping the best way to make it rain is to write about no rain. Let’s see if it works.
To contact David Chinery, horticulture educator for Cornell Cooperative Extension of Rensselaer County, email firstname.lastname@example.org