In late April, walking through the garden section of many stores you’ll see tomato, pepper, squash, and cucumber plants for sale. Does this mean it is safe to plant them now?
Freeze Dates: Data on last spring freeze dates in Western North Carolina are critical to the survival of the warm season plants. In this region of the state, tomatoes, peppers—and often cucumbers and squash—are grown from transplants, not direct seeding. Immediately after planting, they are exposed to the see-sawing air temperature fluctuations that occur during this time of year.
The dates after which there is only a 10 percent chance of a spring freeze (32° F) based on data collected by National Oceanic and Atmospheric Administration (NOAA) from 1981-2010 for selected locations in Buncombe County Western North Carolina are:
Downtown Asheville April 27
Asheville Airport May 4
Fletcher May 7
Black Mountain May 11
Swannanoa May 12
Bent Creek May 13
To be safe, then, Buncombe County Extension Master GardenersSM recommend not planting these crops in the ground until Mother’s Day each year. For your specific location and the weather forecast for any particular year, you may choose to plant earlier or later!
If you do choose to transplant earlier, be prepared to provide some type of frost protection when the temperature is expected to go below 36° F. Techniques for frost protection include covering growing beds or rows with a floating row cover (supported by stakes or wire to keep the material from directly touching the plants). Protect individual plants with plastic milk jugs with the bottoms removed, paper caps, or water-holding walls.
We also recommend “hardening-off” to toughen up your plants before putting them into the ground. Gently stroking your plants a few seconds every day while they are still indoors is helpful. Starting about seven days before you intend to plant, on warm days place your transplants—while still in their growing containers—in the general vicinity of the garden in a protected area to expose them to your intended growing conditions. This is especially important for any plants grown under greenhouse conditions. You will need to make sure they have adequate water and bring them indoors at night to ensure their survival.
Article by Bob Wardwell, Extension Master GardenerSM Volunteer
Learn more:
Hardening off
https://polk.ces.ncsu.edu/2019/03/simple-but-necessary-hardening-off-vegetable-seedlings/
Western North Carolina Planting Calendar for annual vegetables
US Normals Data (1981-2010) for Buncombe County Weather Stations: