COLUMBIA, S.C. — The warm weather and extra time at home have many gardeners more anxious than ever to plant out those summer crops, but are they ready? Late March is a tricky time of year to give the “all clear” for planting frost sensitive plants, but with no major cold in the forecast, I decided to take advantage of the recent warm weather and go ahead with planting. The plants in our garden are not guaranteed to be safe from a freeze. Before you make a decision for your garden, here’s a deeper look at the numbers.
A look at the numbers
The average last freeze in the South Carolina midlands is late March, which means it wouldn’t be unusual to see the last freeze of the winter in the weeks before or after that date. That’s why many gardeners are rightfully hesitant to plant anything tender out until the 1st or second week of April.
Average temperatures are typically measured based on 30 years of data (the current data is 1980 to 2010).
** Average last freeze date for select 30 year intervals are provided below (Columbia, SC)
1989 – 2019 March 24th
1980 – 2010 March 30th
1960 – 1990: April 1st
1940 – 1970: March 26th
** As you can see, the average last freeze of the year on average consistently clocks in late March in Columbia, although recent decades are trending earlier than the mid 1900s.
Let’s talk about the recent century. Since 2000, Columbia, SC has seen an April freeze 4 times (most recently on April 3rd, 2019). The latest last freeze in this time frame was April 16th in 2008. Pretty late right? Well we’ve also had years where the growing season started very early. The last freeze of the season happened in February twice in this time. The earliest was February 21st in 2012.
Why are tender plants going into Gandy’s Garden in late March?
If you’ve read this far, you might be convinced to hold off on planting tender crops until April, yet we’re starting our Tomato and Eggplants in Gandy’s Garden. We aren’t giving the all clear, but the risk for freezing temperatures is low enough for us to start planting. Risk is what gardening is all about and that level of risk depends on the gardener. Gardeners that wait until Mid-April in the Midlands will be at very low risk for freeze damage. Planting the first week of April with a warm forecast like this is also low risk, but there’s always that chance. That’s why we’re not planting out the entire garden with summer crops until the middle of the month and have frost cloths on hand just in case.
The biggest advantage to planting early during warm spells like this is the extra leg up plants will have on growth before the heat gets extreme. In South Carolina, a lot of plants struggle in full summer heat. That’s why we’re giving them as much time as possible to enjoy the mild temperatures in the spring before the heat gets its grip on the garden. Established gardens can handle more heat and drought than recently transplanted gardens.