The only way to change a crop's GGR without 3rd party tools is through Cross Breeding. When two plants cross-breed, the resulting plant will have a GGR score that is between both "parent" plants' GGR. Sometimes it will also be a little bit higher or lower. Thus, to obtain high GGR scores you must go through numerous generations of crossbreeding.
The highest number for GGR is 31.
It is best to start with 4 of the plant you want in a plus-shape with an empty crossbreeder in the middle. This gives the best chance for the "child" plant to be the same as the "parents".
Using Weed-Ex on crops can potentially lower a crop's GGR score too. Thus, you should remove weeds manually if you want high GGR scores.
Pros and Cons
Each statistic has its own pros and cons.
- Pro: The higher the Growth statistic of a plant, the faster it grows.
- Con: The higher the Growth statistic of a plant, the higher the chance of weeds spawning on nearby Crops.
Note: At Growth stat 24 and higher, the plant begins behaving like weeds, destroying nearby Crops. Therefore, a recommended ideal Growth stat would be 20-21, to give a reasonable comfort zone for cross-breeding.
- Pro: The higher the Gain statistic of a plant, the better the drop chance of harvests becomes.
- Con: The higher the Gain statistic of a plant, the lower the chances of dropping Seed Bags.
- Pro: The higher the Resist statistic of a plant, the more resistant it is to weeds and being trampled, as well as greatly increasing the chance of the plant dropping at least one Seed Bag.
- Con: The higher the Resist statistic of a plant, the slower it will cross-breed with other plants.
Note: Crops can still be trampled while sneaking/crouching.