| B. Rosie Lerner
The Good and Bad about Cool, Rainy Weather
Depending on your plants' perspective, our relatively cool, rainy weather
can be a good or a bad thing.
Cool-season plants, such as peas, lettuce, spinach, radishes and pansies,
should be jumping for joy! It's been nearly perfect weather for plants
that get stressed out in hot, dry weather. These plants produce their
best growth and, in the case of the veggie crops, best flavor during such
cool weather. And, of course, if you happen to have a bluegrass lawn,
you and your mower have been spending a lot of time together between downpours!
Unfortunately, many weeds also thrive under these growing conditions.
However, warm-season plants, such as tomatoes, vine crops, sweet potatoes
and petunias, are not finding any cause for celebration. They need warmer
temperatures to establish roots and shoots as the foundation for a good
crop later, be it for roots, foliage, flowers or fruit.
In addition to making poor vegetative growth, many of our warm-season
vegetables such as tomatoes, peppers, beans, squash, cucumbers and melons
must be successfully pollinated in order to produce their fruit. Extreme
temperatures, below 55 or above 90 degrees, will dramatically decrease
pollination. Fruits that do form may appear distorted as they mature later
on. Southern crops, such as okra, lima beans and sweet potatoes, are even
more sensitive to cold.
Seed germination and development of all warm-season crops will be slower
in cold weather, so for late sowings of vegetables, they may be delayed
or may even rot in relatively cold, wet soil. This may also lead to perfect
conditions for "damping-off," a fungal disease that attacks
Thunderstorms have been scattered, so some areas may still be on the
dry side while others may be under water. Excess water, along with cool
temperatures, can cause the appearance of blisters or bumps on leaves
and stems called oedema. This condition is caused by too much water in
the individual cells. Eventually, the cells in these bumps burst and often
become corky and brown in appearance as they dry out. Oedema is not an
infectious disease, nor is it a serious problem. Plants will outgrow the
Whatever the cause of plant stress, gardeners should be ready to water
if dry weather returns. In areas of heavy rains, side-dressing with nitrogen
fertilizer will help replace that which was washed away during the downpours.
And be prepared for more "weather" this summer!