This is a universal terrarium planting kit:
It has three planting materials forming the three layers of a terrarium:
1. The bottom layer is small, 5-8mm lava ( default red; if you want it black, please message me when you place the order). This layer provides drainage for your terrarium, and you can easily see if there is any waterlog.

2. Dry sphagnum: this is the water-absorbing layer. Please sink them in water and squeeze extra water out.
You need to place them above the lava rock and press them flat. They can also fill the rock gaps or make the land slope. There are many videos on my YouTube about how to use them. You can also use them to wrap roots and fix plants in rock/wood gaps.

3. 1-3mm Natural small diatomite rocks. They are the top layer. It helps improve drainage and reduce root rot. One of the best soil rocks for a terrarium. It is porous, allowing good drainage. After spraying water, the small rocks will become sticky and stay in place.

This planting kit is used in almost every terrarium I have made. With them, your terrarium will not leak. You can pour the extra water out easily if you water too much. This is why I choose them.

What is included in the package:

5-8mm lava rock: 800g
Dry sphagnum: 50g
Natural small diatomite rocks: 400g
For your reference, you plant a 20x30cm moss with them.
For the moss: https://shorturl.at/suY47

Those materials are all available in my shop. But I find this planting kit is more simple and easy to choose.

You have all the materials to make a live moss wall terrarium with red clay.
The red clay:
https://www.etsy.com/listing/1285362579