The same rules apply to this promotion as before - you'll simply need to play CastleVille until you reach Level 10, and will the be able to come back to FarmVille to receive a new batch of 10 free Instant Grows. However, there is a slight catch. Instead of being given these Instant Grows, well... instantly, we'll have to wait until December 19 when they'll be given away. At that point, there should be a mass release of these potions to anyone that was eligible for them, which actually gives you plenty of time (almost two weeks) to reach Level 10, if you've yet to do so.
For a better look at getting ahead (and fast) in CastleVille, make sure to check out our tips and tricks.
Will you continue to play CastleVille until you reach Level 10 in order to earn the 10 free Instant Grows in FarmVille? Have you already used the five you received from the first promotion? Sound off in the comments.