Upwelling

{3}{G} · Enchantment

Players don't lose unspent mana as steps and phases end.

Motor: se resuelve a mano

Rulings (1)

Players can keep unspent mana indefinitely while this is on the battlefield, but once it leaves the battlefield, they have until the end of the current step (or phase) to use the mana before it disappears.
Wizards of the Coast · 2009-10-01