Farm Scene for the Salisbury Post
Darrell Blackwelder
June 23, 2002
Erratic weather patterns are have caused many problems
this
season. A few weeks ago I was wearing a sweater looking at the
Rowan County tomato crop. Unseasonal weather that we've
experienced this spring often affects the growth and development
on vegetables, especially tomatoes. I always receive quite a few
questions about tomatoes this time of year.
Tomato plants often have erratic or poor fruit set because
of the temperature fluctuations. Cool, night temperatures
not so long ago during flowering caused some buds to abort
leaving the vine fruitless at the bottom of the plant. Some home
gardeners are complaining of all vine and no fruit on
their plants. Over fertilization with nitrogen at planting also
yields heavy vine growth and low fruit set.
Poor light is another reason for poor growth and fruit set.
Many people put a few plants around the home in flower beds for a
few extra fruit during the summer. Too much shade during the day
makes plants stretch for light becoming weak and somewhat
spindly. These plants need full sun all day long for maximum
tomato production.
Lack of water during fruit set causes some fruit to have
blossomend rot. This condition occurs not only in tomatoes, but
also in squash, and watermelons. Blossomend rot is a calcium
deficiency sparked by periods of drought or in some instances,
too much water. Liming before planting is beneficial, but no
substitute for consistent irrigation. Plants must be irrigated
on a regular basis to prevent blossomend rot. Tomato breeder
Dr. Randy Gardner from the N. C. State University Mountain Crops
Horticulture Research Station has proven that fruit laden plants
may use up to a gallon of water a day during peak growth.
Also, some varities are more predisposed to blosom end rot
than others. It's always a good practice to plant different
varieties for this reason. Commercial growers always try new
varieties to determine growth habits during varying conditions.
Mulching helps reduce the incidence of blossom end rot.
Calcium chloride sprays are available that also aid in the
control of this physiological problem.
Tomatoes plants are normally faced with humid, warm
temperatures have few problems so far with foliar disease such as
early blight. However, Southern bacterial wilt is a tomato
disease also prevalent in Rowan County that is still a problem.
This is a soil borne bacterial disease that causes plants to
suddenly wilt and die, just before harvest. The disease may
strike a few or all plants in a row. Close observation reveals a
darkening of vascular system in stems. The system which supplies
water and nutrients to plant is suddenly clogged by bacterial
breakdown of cells causing the plant to wilt and die. There is
no chemical control of bacterial wilt once the plant is affected.
Crop rotation is the only recourse for home gardeners.
Darrell Blackwelder is an agricultural agent in charge of
horticulture with the North Carolina Cooperative Extension
Service in Rowan County. For archived garden columns or other
gardening information visit the Master Gardener Web site at
www.rowanmastergardener.com or email
darrell_blackwelder@ncsu.edu.