Many home gardeners and commercial producers of strawberries in Iowa have had discouraging results with everbearing strawberries. One reason is the hot, dry weather we usually have during July and August. Because moisture is short, the late summer crop often consists mostly of small fruits or "nubbins"- sometimes not even worth harvesting.
Denisen, E. L. and Crandall, P. C.
"Bigger Yields From Everbearing Strawberries,"
Iowa Farm Science: Vol. 6
, Article 4.
Available at: https://lib.dr.iastate.edu/farmscience/vol6/iss9/4