Success in restoring longleaf pine ecosystems depends on outplanting high‐quality longleaf pine seedlings. One important and relatively understudied attribute of seedling quality is cold hardiness. A suite of trials was conducted to investigate the influence of common nursery cultural practices on longleaf pine cold hardiness. Cold hardiness was increased with higher rates of nitrogen, unaffected by copper coating containers, greater for foliage than for root‐collar tissue, and tended to increase with increases in container size.