by Karen O’Leary
While skeptics can go on denying climate change, gardeners and farmers know better. In our corner of this globally warmed world, a century or more of accumulated growing wisdom is being thrown out the greenhouse door with bathwater and baby.
Last year, the sweet peppers did poorly because a favorite gardening maxim let me down: “six months from the first thunderstorm, expect the first frost.” That adage failed spectacularly when the peppers planted after a warm Mother’s Day drencher were subjected to frost two days – not six months – later. Stunned and stunted, they never recovered.
Another favorite: “Plant peas before the last snow melts” worked well until 2011, when the dog days of August arrived in April. The sugar snaps bolted then broke under the weight of a late snowstorm just as delicate flowers formed the promise of sweet pods. That was followed by another spring heat wave ruining a second crop.
2012 has been no better: the U.S. saw the warmest March on record, a jaw dropping 8.6 degrees Fahrenheit above the 20th century average! This was followed by a damaging frost to New England apples – fooled into blossoming by the March heat wave – in turn followed by more heat records set in April. Apples, plums and pears will produce lower yields this year.
Obviously, you can’t “plant corn when oak leaves are the size of a mouse’s ear” when oaks now delay flowering in response to drastically warmer winters, a just discovered effect called “vernalization.” Studies out of the University of California show that wild plants are adapting to survive climate change. So must we.
This summer – as in future summers – we can expect hotter than normal growing temperatures over much of the U.S. We can also expect drought: it’s already abnormally dry in almost every state, with serious drought in the Southeast, and from California to Texas. (See your region’s forecast at: www.cpc.ncep.noaa.gov/index.php).
I’m adjusting my gardening methods to stay in step. The best way to adapt to the hot and dry is to introduce low or no-tillage techniques that retain soil moisture and subsoil ecosystem health.
Get ready for drought and town watering bans by installing a rain barrel or cistern connected to a passive drip hose system for the garden.
Recyclable mulches, raised beds and ditching will help control and better utilize run-off from much heavier, and more sporadic rainfall – the likely norm for much of the US in coming years.
Learn to use shade. Natural and created sun barriers lessen solar drying of soils and protect cool weather crops from afternoon heat. My Pacman Broccoli produced until July in its shady, mulched spot. Hang shade cloth over June-bearing strawberries and cabbages to reduce water demands and blanching of tender fruits. Short hedges of raspberries or elderberries protect heat-sensitive lettuces, carrots and spinach in adjoining rows. Mulch your beds loosely with straw to make a moist microclimate.
Warmer, earlier springs also mean quicker emergence of insect pests. Contact local agricultural extension services to calculate “degree days” – the number of warm days until overwintering insect adults or young emerge. Put up row covers or sticky traps before the bugs arrive to save sanity and valuable crops.
Change your game further by testing warm-weather plant varieties new to your region. Check the 2012 USDA Plant Hardiness Zone Map (www.usna.usda.gov/Hardzone). It’s the first update since 1990 and reflects significant global warming of 4 to 5 degrees over much of the nation. Now cantaloupes, which barely stood a chance before, are growing in places like Santa Fe, New Mexico, while heat-loving Merlot grapes have become the second most popular variety in Virginia, reports Scientific American.
Finally, prepare as best you can for “whiplash” weather – extremes of hot and cold, dry and wet. Keep cold frames and row covers handy.
I can’t stop climate change. But I can adjust to and perhaps even learn to enjoy the fruits of a warmer, if less predictable, growing zone where Merlot may one day replace maple syrup as Vermont’s signature crop.
Karen O’Leary is a writer, amateur naturalist, and former farmer. A Boston, MA native, she lives in Montpelier, VT. ©2012 Blue Ridge Press.