Gardening in Tennessee: zones, frost dates and when to plant

West, Middle and East Tennessee

UT Extension’s Tennessee Home Fruit and Vegetable Garden Calendar (W 436) gives timing by grand division, and the order is consistent: West Tennessee first, Middle Tennessee next, East Tennessee last. The reminder to start kale transplants for West Tennessee appears in early January, while the same reminder for East Tennessee comes in February. The March page lists the deadline for finishing peas and potatoes in West Tennessee alongside East Tennessee’s earliest date for seed potatoes.

Within each division, elevation matters as much as longitude. The calendar’s frost table shows higher places such as Crossville on the Cumberland Plateau and Mountain City in the northeast mountains running well behind Memphis and Chattanooga; check the city table above for your area. UT Extension notes that stone fruits are especially hard to grow in the cooler parts of the state because they bloom early and late frosts catch the flowers.

Local site matters too. UT Extension’s Site Selection and Soil Testing (W 346-A) explains that south- and southeast-facing ground warms and dries faster in spring, though temperatures swing more there. A gentle slope lets cold air drain away rather than pool in a frost pocket, which can protect early and late crops.

What limits Tennessee gardens

Summer heat. The calendar’s April advice is to finish seeding and transplanting cool-season crops so they do not mature in hot summer weather. Peppers and eggplant like even warmer soil than tomatoes and often go in later.

Uneven rain. UT Extension’s Growing Tomatoes (W 346-H) notes that most years bring dry or erratic stretches in spring, summer and early fall. The calendar calls early fall often the driest time of year in the state, just when fall crops are getting started. Without rain, plan on roughly 1 to 2 inches of water a week. For tomatoes, UT suggests two waterings of ½ to ¾ inch each rather than one heavy soaking.

Disease. Drip irrigation keeps leaves dry and lowers disease risk. The calendar flags early blight on tomatoes as early summer arrives. UT Extension says transplants grown out of state have been a major source of disease in Tennessee gardens, and that bacterial spot is hard or impossible to control once it arrives, so buy locally grown plants when you can. Rotate crop families out of a bed for three years.

Soils. Soils vary widely across Tennessee. Clay holds water so tightly that plants cannot always use it, and sand holds too little. Organic matter helps both. W 346-A warns against working soil that is too wet: if a handful rolls into a ball and won’t crumble, wait.

UT Extension’s calendar, season by season

W 436 lays out the gardening year month by month. Some key points:

• Winter: order seed early, start cole crop transplants about 8 weeks before setting out, and start the earliest warm-season transplants in February or early March for a May planting. Tomato transplants need 6 to 8 weeks.
• Early spring: hardy cool-season crops are usually seeded or transplanted 4 to 6 weeks before the frost-free date, and less hardy ones about 2 weeks before. Row covers and low tunnels push early crops along. Carrots can go in across most of the state in March, and asparagus in early to mid-March.
• Late spring: watch soil temperature, not just air temperature. Supersweet corn and seedless watermelon germinate poorly in cool soil. Black plastic warms beds early, while straw is best added after the soil warms.
• Late summer and fall: transplant the slowest fall cool-season crops first. Allow extra days to harvest because of cooler, shorter fall days. A row cover can add a couple of weeks to the fall season.

Varieties UT Extension names

For fall leafy crops, the calendar suggests leaf lettuces such as ‘Green Star’, ‘Two Star’, ‘Tropicana’ and ‘New Red Fire’, and bibb types ‘Nancy’, ‘Skyphos’ or ‘Red Cross’. For kale it lists ‘Scarlet’, ‘Redbor’, ‘Prizm’ and ‘Lacinato’. For disease-resistant apples it lists ‘Enterprise’, ‘Liberty’, ‘Freedom’, ‘Redfree’, ‘CrimsonCrisp’, ‘Pristine’ and ‘GoldRush’. For peaches with some bacterial spot resistance, it lists ‘Contender’, ‘Intrepid’ and ‘Carolina Gold’. UT also runs a statewide Home Garden Variety Trial in which home gardeners grow test crops and report results.

Soil testing through UT

Fall sampling is most common, so amendments can go on before the next season. Collect 10 to 15 cores 6 inches deep, mix them in a clean, non-galvanized bucket and air dry the soil. Get a box from your county Extension office and send it to the UT Soil, Plant and Pest Center. The basic test reports pH, phosphorus, potassium, calcium and magnesium, with lime and fertilizer recommendations. For tomatoes, UT recommends a pH of at least 6.1, ideally 6.5 to 6.8, which also helps limit Fusarium wilt.