This is a sad story. And like most tales of woe, it came about through a combination of bad luck and fatal error.
Alas, poor brassicas
Weather
Hail damage in vegetable (and other) gardens
Did you get hail last weekend? As is usual with spotty hailstorms, some places were pummeled and some were completely spared. The hail at my house was pea-sized. After the storm, I checked out the damage to my eggplant leaves:
These plants are in pots on my deck (which helps me avoid flea beetles). Not much else in my gardens was hurt, but it got me thinking about writing about hail damage for this blog post. And then MG Pam Hosimer told me about what happened in her garden, not too many miles away. This is the hail she got – !!!
Climate change starting to affect Maryland farms (Viewpoint)
Editor’s note – this article was originally posted on Delmarva Farmer and was re-published here with permission. While the content focuses on farms, it is also relevant to anyone growing in Maryland, including homeowners.
The day I drove to Easton, Md. to discuss climate change with the staff of The Delmarva Farmer, it was raining so hard I couldn’t see the car ahead of me on the Bay Bridge.
It’s easy to write off a torrential rain like that as just another case of bad weather.
However, long-term records of rainfall in the Third National Climate Assessment in 2014 show that much more of our rain now falls in downpours rather than in the gentle soaking rains I remember as a kid.
“Bad weather” is becoming more common.
The increasing frequency of downpours in our region is just part of what scientists call “the new normal” under climate change. In Maryland, data released earlier this year by the National Oceanic and Atmospheric Administration show that the frequency of rains greater than 4 inches has increased since 1950, as have the number of days warmer than 100 degrees F and the number of nights over 70 degrees F.
Seasonal patterns of precipitation have also changed, with more rain typically falling in spring and fall and less rainfall in the summer. Winters are warmer and shorter and spring comes earlier.
These new weather patterns are products of four big climatic changes that began in the mid-1800s: The air is warmer, the ocean is warmer, there is more water vapor in the air, and sea levels are rising.
High Night Temperatures Can Lower Yields
I am in fall gardening mode which means I’m still thinking about some of the state-wide complaints from gardeners about lower than expected bean, pepper, and tomato yields during the hottest weeks of the past summer (mid-June through mid-August). Although many factors can reduce flowering and fruiting I believe that high night temperature is a growing, and overlooked, cause of this problem.
In general, warm-season crops can tolerate high day temperatures but can be negatively affected by higher than normal night temperatures, which hovered around 80°F in Maryland’s urban and suburban areas for most of July. Here’s an overview of this aspect of climate change from the USDA:
Some crops are particularly sensitive to high nighttime temperatures, which have been rising evenfaster than daytime temperatures. Nighttime temperatures are expected to continue to rise in the future. These changes in temperature are especially critical to the reproductive phase of growth because warm nights increase the respiration rate and reduce the amount of carbon that is captured during the day by photosynthesis to be retained in the fruit or grain…. Common snap beans show substantial yield reduction when nighttime temperatures exceed 80°F.
Many of us observed healthy mid-summer snap bean crops with few flowers or pods. Yields increased once the weather cooled in mid-August. Experienced gardeners have lamented poor lima bean crops in recent years. Stink bug feeding has been a problem in beans but increasing night heat could also be at play. Research studies have shown that high night temperature causes sterile pollen and damages flower buds. Cowpea (a heat-loving crop!) yields consistently decline when night temperatures increase from 60°F to 75°F.
On another global warming note… I attended the annual meeting of the American Society for Horticultural Science a few weeks ago and heard an interesting talk on how Shading Levels Affect Bell Pepper Fruit Yield (Juan Carlos Diaz-Perez; University of Georgia). The researchers found that erecting shade cloth over bell pepper plants increased yields. The lowest yields were from completely unshaded plants and the highest yields were from plants with 30% shading. Shading lowered leaf and root temperatures and reduced the incidence of blossom-end rot and sunscald.
So what’s the upshot? Climate change is real and night temperatures are on the rise.
Some garden-level responses? Try providing some shade to pepper plants in full-sun gardens. Plant snap beans multiple times and focus more on spring and late summer plantings. Plant limas late so they bear pods from late August through September. Experiment with planting bean, tomato, and pepper in spots where they will receive some late afternoon shade.