H. Schwartz, Colorado State University, Bugwood.org
Photo 1: Onion seedlings suffering from root rot
Seeds planted into cold soils may sit and wait or may germinate but grow very slowly. In these very early stages of life, seedlings are highly susceptible to soil borne pathogens that cause root rot and damping off. Gardeners may notice that seeds are failing to emerge from the ground or that young seedlings emerge and then yellow and fall over. Older plants may become stunted by root rot. Leaves may wilt and dieback. The recent excess of heavy rain in many areas of the state has created ideal conditions (cool, wet soils) for these root rotting pathogens. Several cases of seedling damping off and root rot of young plants have been reported.
Dept. of Plant Pathology Archives, North Carolina State University, Bugwood.org
Photo 2: Impatiens transplants suffering from root rot
Seeds coated with a fungicide treatment will be protected at the earliest stages of growth. For gardeners that choose not to use treated seed, waiting until soil warms up to the appropriate temperature or using the techniques listed above to heat soil and improve drainage can be just as effective in preventing early season root rot.