We all know the weather can be very hard to predict, especially in North Carolina. We have had a roller coaster recently of warm afternoon temperatures but cool mornings.

As we have warm temperatures, many gardeners get spring fever and want to get started on their gardens and landscapes. One of the challenges gardeners face is when to plant warm-season flowers and vegetables and not risk cold damage from a late frost.

Frost forms on solid objects when the water vapor in the atmosphere changes from its vapor (gas) phase to small ice crystals (solid phase). For frost to form on an object, the object has to reach 32 degrees F or lower. However, the air temperature within the vicinity of the object can be several degrees higher. It does not take long to realize it can be very hard to predict when our last spring frost will be, especially as we have warm spring days and cool nights.

There is lots of variation in the date when we have our last frost in Wayne County. The last frost date has been as early as mid-March and some years as late as the beginning of May. Often many resources give gardeners a guideline by finding the average last frost date. Even though it may sound simple enough to take the average of all the last frost dates over the years, there is much variation in what resources claim as the last average frost date. In doing a search of what different resources say is the average last frost date for Goldsboro, it ranged from March 28 to April 20. The range varies depending on how many years of data are included in the average and takes into consideration how often it does not occur on that average date. We often pick somewhere in the middle and say around April 15 is the last average frost date in Wayne County (think Tax Day). Remember, however, there is no guarantee that there will not be a frost after April 15.

So what are gardeners to do when they are ready to plant warm-season vegetables, like tomatoes, peppers, eggplant, corn, beans, and squash, or warm-season flowers like begonias, impatiens, marigolds, petunias and zinnias in their garden? It all depends on if you want to be a risk taker or play it safe. Some gardeners go ahead and start planting warm-season flowers and vegetables around the first of April knowing that they could lose their plants to a late frost, while others wait until around late April or early May when the chances of frost are much lower.

If you do plant early, you have to be prepared to cover and protect your plants if we do have a late spring frost. Row covers made of light-weight fabric that will be sun- and air-permeable work well for quickly covering plants if a frost is predicted. Many try to cover plants with plastic because it is often what they have on hand for a last-minute solution. Plastic covers usually create more plant damage than good. Plant leaves in direct contact with the plastic can be burned, and if the plastic is not removed early in the morning, you are creating a mini-greenhouse that will quickly overheat your plants and not allow air to get to them. Creating a tunnel using wire or PVC pipe and then covering with row covers or plastic can help prevent plants from coming in direct contact with the material. When covers are used, they should be removed the next morning as temperatures increase to prevent further plant damage.

As you plan for planting your gardens and landscapes, keep in mind that we are not necessarily out of the clear for having a late spring frost. We never know if we have already seen our last frost for the season, but we can always hope that we have seen the last of cool weather this season.

Got gardening questions? We can help! Contact the Wayne County Extension Gardener Volunteer Plant Clinic on Mondays and Wednesdays from 10 a.m. to 1 p.m. One can reach the Wayne County Extension Master Gardener Volunteer Plant Clinic by phone at 919-731-1433, email at Master.Gardener@waynegov.com or stopping by the Wayne County Extension Office at the Maxwell Regional Agricultural and Convention Center, 3114B Wayne Memorial Drive.

Learn more

• Subscribe to Wayne County Gardening e-newsletter and receive timely gardening information and announcements of upcoming extension gardening events. To subscribe, visit http://go.ncsu.edu/subscribewcg. Scroll down to enter your email address in the “address” box and click on the subscribe button. You will then receive an email which will direct you to a website to accept the subscription.

• “Like” us on Facebook to receive timely garden tips, ask questions, and learn of upcoming gardening events. www.facebook.com/waynecountygardening.

Wayne County Extension gardening programs

• The Lawn Care Basics workshop will be 10 a.m. to 1 p.m. Wednesday, May 15, at the Wayne County Extension Office, the Maxwell Center, 3114B Wayne Memorial Drive. The workshop will cover how you can successfully care for your lawn. Learn about site preparation, grass selection, seeding, lawn maintenance and common pest problems. Registration fee is $5. Pre-registration is not required. Arrive a few minutes early to register.

• Visit the Farm Credit Farmers Market, behind the Maxwell Center at 3114 Wayne Memorial Drive. The market is open Thursdays and Fridays from 10 a.m. to 5 p.m. and Saturdays 9 a.m. to 2 p.m.

• Save the dates for our annual Garden Festival and Plant Sale. This year’s festival and sale will be a two-day event, so come early for the best selection of plants. The festival will be open Friday, May 3, from 10 a.m. to 5 p.m. and Saturday, May 4, from 9 a.m. to 2 p.m. The festival will be at the Farm Credit Farmers Market, behind the Maxwell Center at 3114 Wayne Memorial Drive. A large variety of plants, crafts and raffles will be for sale along with Master Gardener volunteers being on hand to answer your gardening questions. Be sure to visit the Farm Credit Farmers Market during the event along with a food demonstration on Friday, May 3, from 2:30 p.m. to 4:30 p.m., and Beekeepers of the Neuse will have local honey for sale both days.

Jessica Strickland is an agriculture extension agent specializing in horticulture for North Carolina Cooperative Extension in Wayne County.