This is a list of the materials that I am using or have tried. Not every one is amazing. I don’t get anything by endorsing products.

Soil components

Garden Pumice 1/8” stone

General Pumice Products, Amazon

This stuff is great. I plan to use it in many mixes. It is light, but not so light that it floats, and has a perfect particle size for my purposes.

Coco Coir

CJQC, Amazon

I just started experimenting with this.

Pine Bark Mulch

Timberline, Lowe’s

This is typical mulching bark that I’ve used many times from Lowe’s. I think they also carry the same brand at Home Depot. I would like a finer particle size, but this is the smallest I can get from my local Lowe’s. I’ve seen smaller versions at other locations.

Indoor Potting Mix

Kellogg, Home Depot

I have not been a big fan of the performance of this potting mix for my purposes. On its own it holds water too strongly and stays too wet. It also tends to form a crust on the surface, gluing the soil together, instead of staying light and fluffy. It does that even when mixed with pumice 50:50. I like that it is organic. I also like that it is mostly wood-based and therefore should wet easily. I think the overall blend just isn’t great.

Vermiculite fine grade

Sta-Green, Amazon