DragonVale Breeding Combinations + Rainbow Dragons

Dragon 1	Dragon 2	Incubation period	Outcome
Plant	Fire	1 hour	Flower
Fire	Earth	12 hours	Lava
Earth	Plant	12 hours	Moss
Fire	Flower	30 minutes	Poison
Plant	Earth	14 hours	Tree
Cold	Earth	14 hours	Mountain
Fire	Lightning	3 hours	Firefly
Earth	Lightning	24 hours	Crystal
Lava	Lightning	6 hours	Quake
Lightning	Cold	5 hours	Storm
Cold	Water	8 hours	Ice
Earth	Water	6 hours	Mud
Plant	Water	9 hours	Swamp
Water	Plant	5 hours	Seaweed
Air	Lightning	8 hours	Sonic
Cold	Air	8 hours	Snow
Air	Fire	8 hours	Blazing
Air	Plant	8 hours	Willow

Some combinations that have been known to produce *Rainbow dragons:

• Snow + Lightning 
• Firefly + Swamp 
• Blazing + Crystal 
• Flower + Mud 

*Level does not matter, you don't need all other dragons, you don't need boosts, you don't need rainbow habitats, nor flags. Its random. Firefly seems to work well with Seaweed or Swamp