ABSTRACTWith the possibility of co‐optimizing all growth factors in vertical farming, such systems could contribute to future food supply, but the potential productivity is unknown. Analyzing 171 publications with 1403 data points across 10 crop categories from controlled‐environment experiments revealed major productivity variation among and within crop species. Potato produced the most edible dry mass of 33 g m−2 day−1, 28 times more per layer than open‐field cultivation. High planting density crops generally showed a high productivity, while crops with longer life cycles were less productive considering time and space. The limits of productivity, defined as the points at which optimizing growth factors return no further benefit, remain uncertain. Uncovering this limit requires systematic, standardized, and scalable controlled‐environment experiments across crop types.