Downy brome grows in many climatic areas. It is found primarily in the 150-560 mm precipitation zone. Downy brome will grow in almost any type of soil. Downy brome has been found growing on B and C horizons of eroded areas and areas low in nitrogen. It grows in a relatively narrow range of soil temperatures.
Litter promotes germination and establishment of seedlings.
Downy brome is a winter annual. It germinates in the fall, over winters as a seedling, then flowers in the spring. If fall precipitation is limiting and spring moisture is adequate, the seeds will germinate in the spring, and the plants will flower that summer. The plants typically flower from mid-April through June. Florets are dispersed within a week of maturity by wind, attachment to animal fur, or small rodents.