Exactly what the title says. It'd make planting much faster if you could simply equip seeds and plant them with one click rather than opening the planter, finding the seed you want, adding it to the planter, then backing out of the menu.
If there's a coding issue with "equipping" a food item, you could add craftable seed bags to the game and change what seeds are in it similar to how you pick ammo types for guns, or add a craftable seed bag that requires X amount of seeds and is consumed after planting X seeds.
Either being able to "hold" seeds and left-click plant them, or having a tool like a trowel or seed bag that you "load" with seeds would be great, maybe give it a secondary option to spread seeds in a larger area for those tightly packed farms . The UI for adding seeds to pots is incredibly clunky, even worse given that the large Plant Boxes only hold one seed like any other farm/growing pot even though it's many times larger, would have thought it could hold 2x2 or 3x3 seeds at least.
Oh yes, bit tedious having to open the plant box/pot inventory and drag-drop the seed over especially if you have a large amount of said boxes/pots. The ability to be able to equip the seed to a quickslot or as mentioned above into a seed pouch would be welcome indeed.