Developing experiential learning opportunities in online courses is challenging, especially in the field of applied plant science. Our goal was to develop an online learning activity for an introductory horticulture course that would increase student confidence in and knowledge about: 1) sustainability tradeoffs in crop production systems, 2) the scientific method, and 3) data analysis and interpretation. To accomplish this goal, we created the Sustainable Lettuce Competition where students worked in teams to make evidence-based management decisions for a greenhouse lettuce crop. They competed with their peers to achieve the best balance of productivity, input use efficiency, and profitability. The suite of management choices for each team constituted one treatment in a virtual experiment conducted by instructors on campus. At the end of the experiment, students received yield and input data to calculate sustainability metrics and test hypotheses. In surveys of student perceptions of their learning, the majority of students agreed that the competition improved their knowledge about experimental design (65% - 81%) and data analysis and interpretation (63% - 79%). And 83% - 87% indicated increased knowledge about sustainability tradeoffs in crop production systems. Direct assessment of student performance (i.e., grades) supported learning outcomes identified in the survey.