At times, potato growers may experience poor emergence of potato plants. There are number of reasons why potato plants may not emerge properly. Potato specialists Andy Robinson, Eugenia Banks and Steven B. Johnson have compiled a list of common problems that can cause poor potato emergence and stand. Utilizing this list can help growers more rapidly identify the cause and improve management of the crop and subsequent crops.
According to the authors of the checklist, planting healthy seed is one of the most important factors that allow growers to produce a high-quality and high-yielding potato crop. Certified seed should give optimum emergence when handled and suberized properly, especially keeping tubers free of bruises or injuries wounds. Optimum soil conditions will increase the probability of a successful plant stand.
The potato specialists point out that soil temperature and moisture are key factors in optimizing crop emergence. Ideally, the soil temperature and the seed temperature should be the same at planting; ideally 50 to 55 F (10 to 13 C). As soils warm, sprout growth becomes most rapid at 68 to 72 F (20 to 22 C). Favorable soil moisture should be in the range of 75% to 85% available soil water.
Seed treatments are available to reduce the incidence of fungal pathogens such as Fusarium, Helminthosporium and Rhizoctonia, but not for bacterial pathogens.
Slow emergence often results from planting in nonideal conditions or using lower-quality seed. But sometimes a poor stand follows high-quality seed and perfect planting conditions. For example, planting good seed in a wet soil, either hot or cold, favors bacterial soft rot, which may result in poor stand. Or, planting good seed in ideal conditions, a poor stand can occur because of herbicide carryover in the soil or herbicide residues in the seed.
Potato emergence can be affected a number of ways, according to the potato specialists who compiled the checklist of common factors that occur before or after planting that can reduce seed emergence. The checklist (that includes detailed color photos) can be viewed online on the NDSU website here (where a pdf file can also be downloaded):
Andy Robinson, Associate Professor and Extension Potato Agronomist North Dakota State University/University of Minnesota
Eugenia Banks, Potato Specialist, Ontario Potato Board
Steven B. Johnson, Crops Specialist and Extension Professor University of Maine Cooperative Extension
Cover image: Fusarium seed piece decay in tubers. Credit and courtesy Eugenia Banks