Transplants that are not allowed to harden-off for a few days outside prior to setting in the field may suffer significantly. It is important to expose all transplants to some normal weather conditions before transplanting so they can become acclimated to light intensity as well as the wind and other field conditions.
Young transplants straight from the greenhouse have tender stems and leaves that can easily wilt and/or burn up in direct sunlight or from the heated reflected off of hot plastic mulch or bare ground. Transplants that are set on bare ground during hot, dry weather can still get too much sun and reflected heat from the soil surface. Symptoms of sunscald injury include wilting without obvious disease symptoms, the bleaching of the stem above the soil line (often on one side), followed by the collapse of the plant. It’s important to be patient, especially during periods of extended, hot dry weather. During these periods of waiting, it might be a good idea to make sure the drip system is up and ready to run.
Once transplanting, make sure the holes in the plastic mulch (black or white) are wide enough to keep the stem from coming into contact with it. ‘Leggy’ transplants that lay across plastic mulch or bare ground are extremely susceptible to injury. In some cases growers will fill in the transplant hole with soil to help keep the transplant upright before between-row herbicides are applied.