half-grown beans
豏 centers on beans that are not yet fully mature: half-grown beans. The meaning is narrow and agricultural, with no clear broader conceptual extension.
豏 combines 豆 (bean) with 兼, which likely contributes the sound. The exact historical development is uncertain, but the bean component clearly ties to the meaning.
The left side 豆 is a bean, and the right side 兼 looks like a hand holding two plants. Picture a farmer inspecting a bean plant that is only half-grown, not yet ready to harvest.
For カン, imagine a can of half-grown beans: can -> カン, and the can is only half full because the beans are still immature.