Friday, July 6, 2012

Beating the Heat

I do not claim to be able to fortell the future, but I was certainly anticipating a hot summer when I filled this old firepit with soil and planted a collection of heat-loving annuals. Since the planter was once a firepit, I chose a fire-inspired color scheme. Black coals, gray ash, yellow sparks and red flames, supplied, respectively by petunia, dusty miller, lantana and coleus. All of these are southern favorites owing to their tolerance of heat and humidity. This summer, they are getting a real workout!

We have been days without rain here in the Tennessee Valley, although some folks have had the benefit of afternoon showers that are a common feature of summer weather around here. In my particular case, we have had no measurable rain in the garden for two weeks, and have been irrigating like mad. Despite the irrigation, the soil is drying out and cracking in places. Shrubs and trees are showing signs of heat and drought stress. No amount of irrigation can make up for a good, soaking rain.

Vegetable production continues largely because of our irrigation. We used 5600 gallons of water last month, according to our utility. This month, I expect the total to be at least double that amount. Fortunately for us, the utility caps sewer charges at 6500 gallons during June, July and August, so gardeners get a small break on the water bill (as do swimming pool owners and habitual car washers).

Fresh, potable water is a precious resource in most of the world, a fact lost on us in Tennessee, where waer is abundant. The city of Knoxville removes barely a tenth of the water that flows past us in the Tennessee River each day. With average rainfall around an inch per week during normal times, we are poster children for the old adage that water is never missed until there is a dry spell. But we gardeners really should always be thinking about saving water, not only because conserving saves money, but because waste is inconsistent with sustainable living. Here are some tips for reducing your water consumption this summer:

Install rain barrels or a holding pond to collect and manage runoff from your roof. It will rain again, eventually, providing you with free water.

Mulch, mulch, mulch. Although much of the water lost from the soil is transpired by plants growing there, mulch helps to keep soil moisture relatively constant between irrigation or rain events. This is important for summer crops like tomatoes and cucumbers that appreciate evenly moist soil.

Irrigate early in the morning or late in the day to minimize losses from evaporation. Use a hand held hose sprayer, rather than an overhead sprinkler. This allows you to give some plants more water, and hold back on water for the more tolerant denizens of the garden. Sprinklers waste a lot of water that evaporates before it reaches the ground, especially on punishingly hot days like we have had lately.

Anticipate summer dry spells and include drought-tolerant plants in major plantings. Most trees and shrubs, especially those native to the region, fare well in summer once established. If you have plants that demand irrigation just to stay alive, consider if they are worth the effort or if you might be wiser to replace them.

After the above was written, the weather finally broke. Thursday evening, July 5, we received 0.66 inches of rain. Unfortunately, the weather system that brought us rain and winds also brought far more severe weather in other parts of the region. Two people died in the Great Smoky Mountains. We accept the rain with gratitude, and count our blessings.

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