Early research showed that GLA concentration in borage oil increased when mean daily temperatures were low the last ten days prior to swathing. This resulted in the general recommendation that borage should not be seeded prior to the first week of June. This resulted in higher levels of GLA and then the borage crop could be swathed about September 10 or immediately after the first hard frost, whichever came first. The seedling is vigorous and emerges rapidly. It forms a basal rosette and has a growth habit similar to canola.
Weeds are a problem if they become competitive before the shoot starts elongating.
No herbicides are registered for use in borage. Borage has good crop tolerance to most grass herbicides, such as Poast, Fusion, Hoe-Grass, Venture and Assure. Borage has poor crop tolerance to all broadleaf herbicides. This treatment controlled tiny seedlings of wild mustard and stinkweed. Volunteer borage also presents a weed problem.