These are small red lava rocks. Small lava rocks are porous, great to let the water go through, and function as a filter. They are one of the best rocks for growing moss, and they are easy to use. With a glass bottle with small lava rocks, moss can grow well.

There are two size options: 1-3mm, 5-8mm.

The 5-8mm is used as the bottom layer of a terrarium to prevent waterlogging. Above the lava layer, there is a sphagna layer and soil. Please check my attached terrariums, the bottom layer, they are the smal lava rockes.

With those small lava rock layers at the bottom of the glass terrarium, you will see immediately if you overwater your plants. It allows you to pour out the extra water easily. Putting in small lava rocks is the beginning step of almost every moss terrarium and succulent terrarium I made.

The 1-3mm smaller size is a decorative rock in the water. It is a suitable size to make your waterpond decent.

In my water pond terrariums, I put the 1-3mm lava rocks at the bottom to keep the large rocks stable and adjust their position.

There are two color options: red lava and black lava. This is the red one; there is a red one in my shop too.

Ideal for plants like orchids, succulents, cacti, and bonsai trees

Size: 1-3mm, 5-8mm
Weight: 700g/ 1.54lb