Use the number of creature cards in your graveyard as the ability resolves to determine the value of X. Seed Guardian will count toward this number as long as it’s still in your graveyard at that time.
2016-01-22
Once the Elemental is created, the number of creature cards in your graveyard changing won’t cause the Elemental’s power or toughness to change.
Reach
When this creature dies, create an X/X green Elemental creature token, where X is the number of creature cards in your graveyard.
