Roots and Shoots: Flood or Drought

Changing rainfall patterns and the garden

By Pamela Doan

Four hundred ppm: that’s the amount of carbon scientists measured in the air last week — the highest level of carbon in the atmosphere in 300 million years. Ppm stands for “parts per million,” and there is a lot of debate about the significance of this number on the planet’s health. Bill McKibben, a leading environmental activist, has an organization called, representing the ratio of carbon in the atmosphere that climate scientists believe is a level that still allows for most life forms that exist now on our planet to continue living and avert major catastrophes.

A rain barrel in action  Photo by P. Doan

A rain barrel in action 
Photo by P. Doan

Gardening tends to make us more aware of our environment. Creating a sustainable environment for plants in your landscape, whether it’s flowers, vegetables or trees, leads to discoveries and knowledge about nature and wildlife, deeper connections to the world around us. Rainfall patterns, temperature and notes about the cycle of growth of plants in a garden journal serve as a written record of observations from year to year.

Although this spring has seemed cooler than normal, 2012 was the hottest year on record in the U.S. Fluctuations in temperature and the severity of weather events will have a huge impact on people trying to sustain plants and trees in their yards. Smart choices about using natural resources effectively help to mitigate the negative impact and lessen the work.

Water, sunlight and nutrients from soil are the essentials for plant vitality. Sunlight can be controlled to a certain extent with a careful choice of location that meets the plant’s needs for full-partial sun or shade. Soil can be amended with organic matter to add nutrients, as I’ve discussed previously in this column, or with lime or sulfur to balance its pH for maximum nutrient intake. Water could be something that nature takes care of itself through rainfall, but it usually isn’t.

Over the past 100 years, rainfall in the Northeast has increased by about 3 inches per year and climate change predictions show that trend continuing. However, the rain doesn’t come in nice, steady patterns. Over the past 60 years, heavy downpours of more than 2 inches of rainfall in a 48-hour period have increased nearly 70 percent, and about 50 percent of our rainfall comes in these severe downpours. This pattern increases episodes of flooding, runoff and erosion. We get water from the sky — it just isn’t in the right place at the right time or in the right amount.

There are a few things that gardeners can do to help manage the impact of our changing weather. Conserving water for when it is necessary is a first step. A collection system maintains a reserve, like a rain barrel. A tremendous amount of rain pours off the roof of a building and can be captured by attaching a collection system to the downspout. I have a 50-gallon barrel attached to the downspout and can hook up a hose or fill a watering can whenever it’s needed. Rain barrels can be purchased at most garden centers or online, but they can be pricey.

Look for classes on building rain barrels, like the one at the Desmond-Fish Library in Garrison on June 22, hosted by the Cornell Cooperative Extension. For a $45 fee that covers materials, everyone can go home with a 50-gallon rain barrel that’s ready to go.

Mulching plants and trees helps keep the roots cool and wet during hot, summer days. Use wood chips that are at least a year old or shredded leaves and keep the mulch clear of the plant’s stem so it can breathe. Avoid over- or under-watering plants. Plants need 1 inch of water each week. Place a tuna can in the ground in your garden, and if it’s full each week, keep the sprinkler turned off.

It may be time to evaluate what’s growing in the yard, too. Plants that will thrive in our changing climate are drought resistant and will take up fewer resources and energy. Adapting to new realities means our plants must withstand extremes of temperature and water availability. When making choices about new landscape additions, consider these factors, too. For good plant guides, look online. Many nurseries offer helpful guides, but nonprofits or academic institutions that do research are usually more science-based and don’t have a profit motive. Enjoy the rain this week!

Garden questions? Send them to [email protected].

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