The recent stretch of extremely hot weather is frustrating for those of us who enjoy working in our gardens and seeing summer blooms and harvest.
Master Gardeners who volunteer for our Lancaster County Garden Hotline recently sat down with horticulturalist and Penn State Extension educator Tim Elkner to discuss the problems residential gardeners are experiencing because of extreme heat. Here are challenges brought on by the high temperatures and possible remedies.
Water woes
Rainfall has been somewhat spotty this summer, but most of us in Lancaster County are receiving very little. While it is usually recommended that gardens receive 1 inch of rain per week, the high temperatures may necessitate irrigating gardens with an inch of water two to three times per week.
Watering should be a long, slow application directly to the soil; sprinkling plants daily can do more harm than good. New shrubs and trees should receive water additional to rainfall for five to six years. Lawns that have turned brown are protecting themselves by becoming dormant.
At this point, the return of natural precipitation is the only thing that will restore dormant lawns’ green color.
Less disease, but pests persist
Plant diseases are often spread by high humidity and water splashing on soil, which moves pathogens. Except for powdery mildew, spread by humidity and moisture earlier in the summer, we are seeing few problems from plant disease.
On the other hand, Elkner warns that thrips and spider mites, almost microscopic pests that suck the sap from many types of plants, will run rampant in stressed plants during hot, dry weather.
In addition, you might see more damage from wildlife, such as deer, groundhogs and raccoons, because they are seeking moisture from plants that they do not normally feed on. The usual pests in the wasp and hornet family will make a strong appearance soon, unaffected by the weather conditions. One bright note is that Japanese beetles seem to be having trouble emerging from the hard, dry ground this year.
Trouble in the vegetable garden
Expect to see blossom end rot in tomatoes, peppers and squash. Blossom end rot is blackening and shriveling on the end of the vegetable that is farthest from the stem and is exacerbated by uneven watering.
If you are able to give vegetable plants a deep watering two or three times per week, you can avoid this condition. When weather conditions improve later in the summer, fruit should stop showing signs of blossom end rot.
Another consequence of extreme heat is that our beloved tomatoes drop blossoms, and fruit on the vines does not ripen. When temperatures are above 85 degrees, tomatoes are extremely slow to ripen or stop completely. If tomatoes have started to show any color, you may ripen them indoors.
We can all hope for a return of precipitation and more moderate temperatures as summer continues! Remember that we are here to help with your garden issues. Contact our Garden Hotline at LancasterMG@psu.edu or 717-394-6851.
Lois Miklas is a Penn State Master Gardener for Lancaster County, and a former area Master Gardener coordinator.
