Even with the same amount of sunlight and water, not all plants grow at the same rate. There are many reasons for different rates, and soil is one of them. If the soil is not compacted well or if it is short of nutrients, plants grow slowly.
In God, we receive the words of the water of life and the spiritual food for our souls.
If we feel like our faith is stagnant, we ought to look back whether our mind field is well plowed.