A new thirst for paint and color in cities made extensive flax production profitable in the northern Great Plains and Prairies and contributed to the cultivation of the most fragile grassland ecosystems. The production of flax seed for linseed oil became an early spin-off of the Prairie wheat economy but, unlike wheat, flax vanished from old land after one or two rotations and reappeared in districts with the most new breaking. Officials explained the migrant crop as preparing native grasslands for cultivation or exhausting soil in old land, but farmers brought flax to their new breaking for other reasons. Producers would only put flax on any land when a range of economic and environmental conditions were in place. It was never sown without promise of adequately high prices or in the absence of affordable seed and other inputs. When price allowed, it usually appeared on new breaking because it could be planted later and transported further without upsetting the balance of other activities and without farmers learning many new techniques. Scientists discovered that diseased soil drove flax off old land, not soil exhaustion. Circumventing the disease was possible but costly, and farmers simply replaced flax with the next most lucrative commodity.