Flower soil is used to create terrain that has small natural flowers on it, a pleasant look for many player builds.
Flower Soil Location
Flower soil can be mined up by players for various decorative uses. However it is a fairly rare resource in the game, and thus far I have only found one location for it.
First: fast travel to Ancient Spire – Springlands Fast Travel.
Second: Jump off the Ancient Spire and glide to the Harvest Homestead location on the map.
Third: Once you land, run to the church area. Outside the church, you will see various flower beds. Mine the flower beds, get the flower soil.
Once you have the flower soil desired, you can then use it for building. So long as you have not put a flame in the location, the soil will replenish.