In a Nutshell
Six farmers compared three or four lettuce varieties, Coastal Star, Hampton, Magenta, and Muir, to determine which produces better during summer months (harvest July – Sept.) in Iowa.
Key Findings
Magenta had the highest yields on three of the six farms, and was much more heat tolerant than Coastal Star. Coastal Star produced sizeable heads – particularly in earlier successions – but tended to bolt quickly. Farmers found they could grow quality summer head lettuce using these varieties, though specific preferences differed by farm.