This note reports the results of an inventory study about the influence of the external factors temperature, light, nitrate, gaseous environment of seeds and moisture on the dormancy, germination and emergence of weed seeds. The inventory was made as a guideline for research aiming at the development of weed control methods that make use of these factors to prevent or stimulate germination of weeds in Dutch organic agriculture. Using the available techniques there is still a notable amount of weeds left in the row that has to be removed by hand. Bottlenecks concerning labour are mainly caused by the need to remove these weeds, especially in slowly growing crops. Focus in this study was on the effects of light on the germination and emergence of weeds (seeds) since this factor is relatively easy to alter in the field and is important for germination of seeds for many specie