The theory behind this effect is thought to derive from the physical intermolecular interaction that occurs between compounds in a supersaturated solution (or possibly vapor).

This interaction can potentiate intermolecular forces between the separate molecules and form a basis for a crystal lattice.

The placement of a seed crystal into solution allows the recrystallization process to expedite by eliminating the need for random molecular collision or interaction.

By introducing an already pre-formed basis of the target crystal to act upon, the intermolecular interactions are formed much more easily or readily, than relying on random flow.

Seeding is therefore said to decrease the necessary amount of time needed for nucleation to occur in a recrystallization process.