This can be planted to grow a mahogany tree. The Mahogany Seed is a seed that will grow into a Mahogany Tree in Stardew Valley. It can be obtained by shaking or chopping down Mahogany Trees ...

So, sowing seeds from January through March or frost seeding is mimicking what would have occurred naturally. By doing such, you are taking advantage of the freezing and thawing cycles of the soil.