Gardening Tips: August 1, 2012

Drought
The weatherman is calling for severe weather today as I write this on July 26. I hope that includes some significant rain and not just wind, lightning and hail!
Much of the region has had some beneficial thunderstorms this past week but we are still seriously dry as is most of the country. Heavy rain that falls too quickly often runs off before it can percolate into the soil. We need slow, sustained, three or four days of rain to begin to relieve the current situation.

Signs of drought are obvious as I drive around. Many trees such as birches and shadblow as well as red maples have dropped lots of their leaves. As much as half of their canopy is now on the ground and we will not get to see these leaves turn color this fall, sadly. This will not harm them at all in the long term. I am more concerned about trees that have all their leaves turn brown and shrivel up. I have observed this on black birch, hickory and especially black locust. If they have not yet formed next year’s buds they will perish most likely.

Tips for coping with drought
Here are some tips for coping with the current dry conditions. Some of these might be called “rules of thumb” for any given situation. This makes me wonder exactly who “thumb” was or is? Seems like he or she has a lot of clout and is right about things most of the time. Maybe “Thumb” should be running for President?

Anyway, newly planted trees and shrubs need to be watered once per week for the entire first season they are in the ground right up until November if precipitation is less than one inch per week. The second year, water once every other week and the third year, water once every three weeks. By the fourth year they should have developed enough of a root system to survive droughts such as this.

As for annuals and perennials, including most vegetables, my philosophy is to water only when they wilt in the early morning or evening. Many plants will wilt on hot, sunny afternoons even when soil moisture is adequate. Surface watering of these plants every day only encourages shallow rooting, thus exacerbating the problem. Tomatoes, peppers, and most other vegetable will develop a deeper root system if forced to do so.

Forget about watering the lawn unless you have unlimited sources of water provided by a surface water source, such as a pond. Your deep water well is not unlimited and groundwater recharges very slowly. I have already heard of some wells going dry this summer.
Use mulches as much as possible to retain surface soil moisture. Organic mulches such as wood chips, straw, grass clippings or bark chips should be applied after rainfall or thorough watering. A four-inch layer is adequate, more will do no good and may harm the plants.

Volcanoe watch
Avoid creating “volcanoes’ with mulch. Mulch also smothers weeds that suck up water. Black plastic mulch actually provides a vapor barrier to any loss of surface water through evapotranspiration. Vegetable crops grown in black plastic mulch that has been sealed by covering the perimeter of the plastic with soil NEVER need to be watered if the mulch was applied when soil moisture was abundant.

Collect as much rainfall runoff as possible. Position rain barrels under downspouts to take advantage of thunderstorms. I attached a gutter and downspout on just one side of an eight-foot long shed on my property and it takes only about an inch of rainfall to fill a 55-gallon drum. That 55-gallon drum will water my raised beds for two weeks or more.

Use “grey water” left over from washing dishes or doing laundry for watering trees, shrubs and other ornamentals unless you have used bleach in the water.

Finally, look for plants that are drought tolerant for future plantings. Lists of such plants are available from your local office of Cornell Cooperative Extension.