Seeds of false cleavers (Galium spurium L.) grown in mid-May germinated 12 to 14 days after planting in central Alberta. The plants flowered from early July to late August and developed fruits from mid-July to early September. Plants from the late-June sowing date developed fruits until early October unless early fall frost killed the plants. Plants from seeds sown after mid-July remained in a vegetative state until late September and did not flower. Seedlings that emerged in August and September survived a mild prairie winter and resumed growth the following spring. Under greenhouse conditions, plant height ranged from 77 to 113 cm and the number of branches at first node ranged from 6 to 14, as plant density decreased from 16 to 1 plant/pot. Shoot dry weight decreased by 50% as plant population doubled, 46 days after emergence. The number of seeds produced/plant decreased from 3500 to 175 as plant density increased from 1 to 16 plants/pot. In growth chamber studies, plant growth was greatest at 20 compared to 16 or 24C.