The series of slices (right) off the compound bud of 'Baco Noir' grape begin near the apex of the bud (A) and progress through the three buds in the grape "eye" to the base (F). Photos courtesy of Dr. Thomas Zabadal, Michigan State University.
The primary bud is the least hardy and the most fruitful. To evaluate for injury, look down at the pointed top or apex of the compound bud and slice off the top quarter with a razor parallel to the base of the bud. If the primary is alive it will be bright green in the center. It will be brown or black in the center if it is dead. If you are unfamiliar with this technique, begin at the tip of the compound bud and slice it until the three single buds are seen. Slice below these buds in the cambial region of the cane to learn to distinguish the more olive green smooth textured cambium of the cane from the brighter green bud center with concentric rings of tissue.
The buds A and B are cut too shallow for evaluation of the primary bud.
The buds C and D are properly cut for evaluation of the primary bud.
The buds E and F are cut too deep for evaluation of the primary bud.