For Chattanooga in the south to Johnson City in the north, skirting along the Cherokee National Forest, Sunset Magazine has this to say about planting in this region: "Growing season: May to late Oct. Thanks to greater elevation, summers are cooler and less humid, winters colder (0 degrees to -20 degrees F/-18 degrees to -29 degrees C) than in adjacent, lower zones. Rain comes all year (heaviest in spring). Late frosts are common." Vegetable gardeners will have to be strategic to get a good yield in this climate.
Getting the Most Out of Eastern Tennessee's Growing Season
The weather is important for any gardener, and certainly no less for those with a good view of the Appalachians. The only way to ward off surprises from late frosts is to know what the weather normally does in a given part of the month, and what it is likely to do now. Enter the Internet. Weather sites like Intellicast.com and AccuWeather.com keep records of averages for regions all over the U.S. They also constantly update their forecasts based on the satellite data. It sure beats interpreting the thickness of muskrat nests and rings around the moon. Another useful site is the USDA Plant Hardiness Zone Map, which lists Eastern Tennessee in Zone 6. Many gardening authorities refer to this zone when dispensing advice.
In a normal year, Zone 6 enjoys frost-free days from around April 15 to October 15. When selecting seeds, be sure to get short-season varieties of those plants that like summer heat, like melons and tomatoes.
Many vegetable crops transplant well, so get a jump on the season by starting seedlings indoors. Seed packets carry instructions like "start indoors six weeks before the last frost date." Count back from Tax Day, to start seeds in pots the first week of March. Bottom heat from a seed warmer is handy to speed things up, but any sunny windowsill will do.
Hardening off is critical before transplanting young plants outside in Eastern Tennessee. Over a two-week period, introduce the seedlings to the outdoors for just a couple of the warmest daytime hours at first, gradually increasing the time. This allows the plants to thicken their cell walls with carbohydrates that blunt the effects of the chilly spring temperatures.
Prepare the outdoor garden beds, preferably in the fall before the snows come. Eastern Tennessee soil tends to be acidic in nature, with clay that holds in moisture. The optimal pH range for most vegetables plants ranges from 6.8 to 7.0, which is just slightly acid. Test your soil, and if it is too acidic, sweeten it by adding in wood ashes or lime. You will also want to add in as much biomass as possible, to make the ground easier to work. Cover beds with at least a foot of leaves in the fall, and add compost in the spring.
Water is less of a concern in Eastern Tennessee than in many other parts of the country. If it does not rain for a week or so in the summer, check that the roots are still in moist earth. If they are stressed, yield will diminish and pests will be able to cause more damage.
As the weather gets colder and nighttime temperatures start to dip below the mid-50s, cover vegetables with row cover or something similar to hold in the daytime heat and encourage the last fruits of the season to ripen.
Six months is plenty of time to get a good yield from a vegetable garden in Eastern Tennessee's Zone 6.