Nether Wart not growing

I went to the nether, explored a fortress, and left with nether wart(only 1). I started growing it by placing it on soul sand. It is in the Overworld, and it is not growing. I researched on the minecraft wiki and they said nothing changes the way they grow, weather, lighting, dimension, etc. Please solve it quickly EDIT: It is 1 AM and I was idle in the nether growing it on a block that I had not broken. It grew but I broke it and it wont grow back.