Soil level is a bit of a mysterious thing that you will find at your farm. You can interact with it by selecting the signpost that has a black heart on it next to the path out of your farm. You can spend the heart dust from dead planimals to level up the soil on your farm, but what does it do?
Soil level is actually incredibly valuable and it is essential you level it up if you want to beat the game. The catch is that it does not work in the way that you think it does.
Soil Level Makes Planimals Stronger
The current level of the soil directly relates to the level of the planimals that grow from the soil. So if you have a soil level of 10, that is the level that the planimal will be when it grows. This is very useful when dealing with the dungeons as it will give you much stronger animals to fight with from the very start rather than having to rely on winning battles to level up.
Another benefit of the soil level is that it will level up existing planimals in your party or in the pen. As soon as you purchase the upgrade you will notice that the planimals you are currently using in combat will now have gone up whatever number of levels you just added to the soil.
Does Soil Level Increase The Value Of Crops?
The soil level does not appear to have a relationship to the value of the crops that grow. When you grow them and sell them at the consignment board, you will still get the same amount of money no matter what the soil level is.
The increase in quality is only applied to the planimals that you use for combat when combining crops with a red slime.