Terrarium is sold in 250ml - 500ml - 1 liter and 2 liter portions

If you do not need the portions here or are a beginner - Here is the easy solution
 
Sterilized terrarium soil is a specially formulated substrate, designed to provide optimal conditions for plant growth while minimizing the risk of pathogens and unwanted contaminants. This soil is sterilized to eliminate harmful microorganisms, weed seeds, and potential pests. The added bonus is that it also assist in fungal bloom control.
 
The sterilization process involving heat and steam in a autoclave, this not only ensures a clean and disease-free medium but also promotes a healthy balance within the terrarium ecosystem. By reducing the presence of competing organisms, sterilized soil allows the terrarium's intended inhabitants, including plants and microorganisms, to flourish without the hindrance of detrimental factors.
 
This introduction highlights the importance of using sterilized terrarium soil as a fundamental step in creating a vibrant and resilient microcosm. The sterile foundation sets the stage for a flourishing terrarium, fostering a harmonious balance between soil, plants, and other living components within this captivating miniature world.

PS – ensure that you remove as much soil as possible from plant before introduction.