Problems May Occur When Growing
Tomatoes
Allen Robinson: Ask A Master Gardener
Sunday, May 12, 2019
Q: My family loves to
eat fresh tomatoes off the vine, but I hear that growing tomatoes around here is
a challenge. Can you tell me why it is difficult to grow them here and what I
can do about it? Stacy H., Tulsa
A:
You are certainly not
alone both when it comes to loving tomatoes fresh off the vine as well as
having trouble growing them in northeast Oklahoma.
One of the most common issues is known
as “blossom drop,” which occurs from incomplete pollination. Weather is the
chief cause of inadequate pollination in garden-grown tomatoes, with the most
important factor being temperature. Effective pollination stops occurring once
night temperatures are consistently over 75 degrees and/or when daytime
temperatures are consistently over 92 degrees — especially if it is windy. Too
much rain or too high or low humidity are additional weather factors which
reduce pollen fertility. Also, overapplication of nitrogen fertilizer leads to
blossom drop as well as tall, lanky plants and other diseases.
The solution to this is to plant very
disease/pest resistant and healthy plants as soon as possible after the last
frost has occurred. Then, pick the fruit as soon as it turns pink and let it
continue to ripen indoors. Do not let it sit on the vine until it becomes
overly ripened and soft.
Another common issue is called “blossom
end rot,” where the fruit develops blemishes on the blossom end of the fruit.
This is caused by a calcium deficiency in the plant when the fruit is young.
Overwatering, either from nature or the gardener, is the most common cause
rather than the lack of calcium in the soil. Keep the soil evenly damp as much
as possible.
Skin splitting, called “cracking”, is
also caused by plants going from too little to too much water. Be consistent
about watering. Mulch plants to provide consistent moisture and temperature at
the root level. Be careful to not mulch directly against the plant trunk as it
can lead to diseases.
Speaking of diseases, avoid splashing
soil on the plant and onto tomato fruits, as this carries related fungi and
bacterial diseases. Instead, use either a soaker hose or drip irrigation
system, or carefully water at the base of the plants. Avoid damaging tender
roots by not hoeing too deeply or too closely to the plants.
In addition, there are several pests
that love to live off the stems and leaves of tomato plants. For a listing of
pests and how best to battle them, go online to tulsamastergardeners.org and search for
OSU Fact Sheet EPP-7313 (Home Vegetable Garden Insect Pest Control).
Experts will say that the best weed
control in a lawn is to simply grow a healthy, thick lawn which tends to crowd
out weeds. The same is true for vegetables. Look for high quality varieties at
reputable nurseries around town and ask which varieties are the most disease
resistant. There are many varieties available.
Tulsa’s climate is a challenge to
growing tomatoes in the summer. But, with a little attention to the details,
you can have very good success. And, remember, there’s always fall.
Garden Tips
• Don’t spray
insecticides during fruit tree bloom or pollination may be affected. Disease
sprays can continue according to schedule and label directions.
• Mowing of
warm-season lawns can begin now. Cutting height for bermudagrass and zoysia
grass should be 1 to 1½ inches high, and buffalograss 1½ to 3 inches high.
• Harden off
transplants outside in partial protection from sun and wind prior to planting.
• Let spring flowering bulb foliage remain as long as possible
before removing it. That will allow the energy from the leaf to flow back into
the bulb for flower production next year.
• Prune roses just before growth starts and begin a regular
disease spray program as the foliage appears on susceptible varieties
