Mutagens are a powerful tool for improving your Hempire Cup strains beyond their ordinary limits.
 
Normally, a father strain can only provide a set bonus per level. Once that strain's bonus has been used up, you need to use other strains to maximize all three qualities of your Hempire Cup strain to level it up.
 
However, adding a Mutagen to the mix allows you to breed an additional 50% of the father strain's original max bonus. The extra amount added depends on how much of the bonus you've already used up (e.g. if you haven't bred with that father strain yet during that level, you won't get any bonus).
 
The more you’ve used a strain, the more valuable it is to use a mutagen. You can use mutagens as many times as you like with the same strain, effectively giving any strain limitless potential in the breeding lab.  
 
In other words, mutagens let you get it—referring to your strain quality, of course—up as many times as necessary.
 
Mutagens can be won from calling back trains in your Train Depot! They can also be won from Reward Wheels, including the Daily Rewards Wheel, as one of the randomized categories.
 

STEPS TO USE:

  1. In the breeding lab, put your Hempire Cup strain in the mother strain slot.
  2. Put a strain you’ve already bred with in the father strain slot.
  3. Add a mutagen to the mutagen slot.
  4. Breed your beautiful bud.
 

TIPS:

  • For best results, use a mutagen with a strain you have bred with repeatedly. If the green “bonus” area of the properties doesn’t grow much when you add a mutagen, try a different father strain.
  • The stronger the father strain, the more value you get from adding a mutagen. We hear mutagens and Legendary Buds work well together.
  • Drinking mutagens is not advised. Anyone who says they’re grape-flavored is lying.
  • Mutagens don’t take up storage space in your warehouse. The physics involved are quite fascinating.
  • You cannot use mutagens to improve anything other than Hempire Cup strains.
An image helping explain where and how to get Mutagens.