I love finding a real life “know it all.” Someone to call, especially when I want information on gardening, landscaping or household pests.
The University of Tennessee Extension agents are a great resource with a wealth of information. And they are ready and willing to answer your questions, no matter how quirky.
All 95 Tennessee counties have an extension office with knowledgeable and helpful agents, who are college graduates with specialized knowledge. The agents’ specialties include agriculture, animal health, “homemaking issues,” family money management and youth development, aka 4-H.
During the spring, there are a lot of questions about lawn and garden issues, according to David Cook, who has been an agent for 24 years and fields 200-300 questions every week through email and phone calls.
“We are here to help,” Cook said.
The advice he and other agents give is based on scientific research and comes from a lot of experience. “I learn something new every day. At least that’s my goal,” he said.
Here are a few of the most frequently asked questions that Middle Tennessee agents get this time of year, according to Cook and fellow agent Dan Harrell.
When can I plant tomatoes?
“Our average last frost date in Davidson County and Middle Tennessee is April 15. Late April to early May is the best time to plant tomatoes outside,” said Harrell, who added that other warm-season crops — including okra, corn, cucumbers, squash, beans, peppers, watermelon, cantaloupe and pumpkin — should be on the same schedule.
What is an heirloom tomato?
Harrell said most tomato plants are labeled “hybrid” or “heirloom.”
“Hybrid plants are those that have been crossed for certain beneficial characteristics. For example, one of our prominent tomato diseases is early blight. It is a fungus that attacks the lower leaves on the plant. Many of our hybrid plants have been bred to be resistant to early blight, therefore beneficial to the plant. Heirloom tomatoes are varieties that have not been crossed. Typically, they are at least 50 years old and have been handed down for generations. Their seeds can be saved and grown again. Many believe they have better taste.”
He said hybrid tomatoes include: Better Boy, Early Girl, Celebrity, SuperSweet 100, and Roma. Heirloom tomatoes include: Bradley, Pink Brandywine, Arkansas Traveler, Cherokee Purple and Mortgage Lifter.
How tall tomato plants can grow also factor into their labeling. “Certain varieties of tomatoes have been bred to grow a certain height and don’t have to be caged or staked. These will be labeled ‘determinate,’” Harrell said. “’Indeterminate’ plants can grow up to 6 or 8 feet tall and must be caged or staked.”
When is the best time to start fescue seed on a lawn in Middle Tennessee ?
Cook says the best time to sow fescue seed is late August to mid-October, when “both soil and air temperatures are starting to cool down, which favors fescue seed germination.
“Starting seed in late summer to early fall will give the young grass plants a head start on developing their root system before winter arrives. Fescues may be seeded in early spring, but spring plantings often result in greater susceptibility to heat and drought stresses. Young fescue plants with limited root systems often do not survive the summer heat and dry conditions.”
When is the best time to prune spring and summer flowering shrubs?
Cook says you should prune based on when the plants flower.
“Plants that flower in spring form their flower buds at the end of the summer of the previous year. If you prune in winter, you will be removing flower buds, and the result will be no flowers in the spring.
“For spring flowering shrubs, the best time to prune is immediately after they have finished flowering. Summer flowering shrubs form their flower buds on new growth each spring. Late winter to early spring, just before new growth begins is the best time to prune summer-flowering shrubs.”
Why would my hydrangeas not bloom the last couple of years?
Cook says there could be several reasons for hydrangeas not blooming depending on what kind of hydrangea it is.
“A newly planted bush may bloom the first year if it set flower buds while it was confined to a pot, and then not bloom again for a year or two as it settles into the soil in its new location. Hydrangeas are all moisture-loving plants, so if drought occurs at the wrong time, flowering may not occur.
“Sometimes, gardeners have pruned the hydrangeas at the wrong time (they should be pruned after they flower). In our area, the most common reason is a late spring freeze, which can kill new flower and leaf buds.”
Are Knock Out roses as good as they are cracked up to be?
Cook said Knock Outs are popular because they bloom multiple times through the summer and into fall, and they are shrub roses that can be pruned almost any time, any way. But he warned that, like all roses, they are susceptible to rose rosette, a disease that will destroy them and spread to other roses. While there is no disease-resistant rose at this time, he said there is promising UT research for one.
When is the best time to fertilize a newly planted tree?
According to Cook, the best time extends from late fall, after the leaves have fallen, through the winter and into early spring, before active new growth occurs.
“Fertilizer applied in the fall has a longer time period to penetrate the soil, enabling the roots to more efficiently absorb it. The fertilizer is absorbed by the roots during the winter and is available to the plant for growth in the spring.
“In Tennessee, nitrogen fertilizers should not be applied to trees between Aug. 1 and Nov. 15. The nutrient will promote new late-season growth prone to low temperature injury and reduce the winter hardiness of the tree. Similarly, heavy nitrogen feeding may increase winter injury in many other landscape plants. Fertilization and soil amendments should be based on a soil test report.”
Will too much mulch hurt a tree or shrub?
“Even with the many benefits of mulch, improper application can have a detrimental effect on trees,” Cook said, adding that most plants are sensitive to the depth of mulch.
“More than 4 inches of mulch restricts soil oxygen exchange with the roots. The effect is similar to planting trees deeper than they were grown in the nursery. Roots will have a tendency to grow upward into the mulch to gain better access to oxygen. Thus, instead of the roots spreading outward throughout the soil, they will congregate in the mulch.
“Excessive mulch can lead to accumulation of moisture in the root zone, as well as moisture deficits during droughts, making roots more susceptible to rots, insects and disease.”
How do I test my soil?
Soil testing is performed at the University of Tennessee Soil, Plant and Pest Center at 5201 Marchant Drive, Nashville. The cost is $15, and each country extension office has a soil kit that comes with directions of how to get your soil tested. Results are usually available in about a week, and the county agents will go over your results and recommendations if you ask.