Plant biomass is the basis of our diets and ecosystems, and a promising renewable source of energy and materials. The demand for biomass is increasing, but space limits our capacity to deliver enough biomass to meet food security, bioeconomy, and conservation targets, and climate change threatens productivity further. This Voices asks: which should be the priorities for plant biomass and what are the main limits to achieve them? Plant biomass is the basis of our diets and ecosystems, and a promising renewable source of energy and materials. The demand for biomass is increasing, but space limits our capacity to deliver enough biomass to meet food security, bioeconomy, and conservation targets, and climate change threatens productivity further. This Voices asks: which should be the priorities for plant biomass and what are the main limits to achieve them?