Growing Particle Effect

I’m finding out that particle effects are a bit of an achilies heel in unreal for me and I’d like to remedy that. I’m trying to make a particle effect that looks like mold that slowly starts growing larger. I’m thinking large green splotches. I don’t really know where to start, so any help would be appreciated!

Get yourself familar with this:

For “Growing” Particles, you need to use the “Initial Size” and “Size Over Life” Modules.
The Initial Size determines the Initial Size of the Particles in relation to the Emitter Lifetime.
The “Size over Life” Module is a multiplier in relation to the Particle Lifetime.

The “Initial” keyword is somewhat misleading in conjunction with Size over Life. I would rename “Initial” with “Base”, since it is a constant value for the Particles and is multiplied with Size over Life.