The amount of time in ticks a creature must wait before growing another unit of radius in size. The initial GrowthWait is defined in such a way that a creature will reach full size or MatureRadius after one half of the LifeSpan.

Each tick GrowthWait will drop by one. Once the GrowthWait reaches 0 the creature will grow if it meets all growth requirements. Growth will happen automatically as long as the requirements for growth have been met.