Requires SMM to manage the custom menus, for both my convenience and for the safety of your menus.
CREAtive Gardens has its very own menu found under Decorations.

Seasonal changes are manual and most objects are available as seasonal and non-seasonal forms (so you could put a non-seasonal variant in a greenhouse and a seasonal variant out in the weather).

Changing Seasons on objects in-game requires:

  1. Building the Seasonal versions of objects (Seasonal objects have their own menu).
  2. Installing a CREAtive Gardens Seasonal Add-on.
  3. Loading the Seasonal Add-on below CREAtive Gardens in your load order.
  4. You can safely change the Seasonal Add-ons whenever you like as they are empty .esps