Both marijuana and hemp are cannabis.

As of January 15, 2020, The U.S. federal government and most states consider plants with tiny amounts — 0.3% or less — to be hemp. Anything above that is marijuana and illegal under federal law.

The problem for growers is that hemp is a notoriously fickle crop. Conditions such as sunlight, moisture and soil composition determine its ratio of THC to CBD. Choosing the right harvesting window is critical to ensuring it stays within acceptable THC levels.

CBD oil can be made from hemp. Here is how to make it at home.