This soil mix I am designating “Soil Mix 4”. Technically it is not a mix because it has only one ingredient…but I’ll keep with the theme that I am using for other mixes.

I may also refer to this mix as 1/4”-minus screened bark. Very catchy.

Starting material

I am using Timberline bark from Lowe’s. This material does not cost much. I might be able to save time by purchasing specialty bark that is already the correct size, but everything I’ve seen online is quite expensive.

It is large chunks of bark.

Screening

I am screening this with a 1/4” screen.

Even though the chunks are large, I am not trying to modify the particle size. Instead I am just sifting out the small pieces for my soil.

The yield of planting mix from this process is very low. One bag (2 cubic feet) yielded about 1 gallon of screened material. But nothing is wasted because I need the bark in the yard for mulch. I just do this process out in the yard and dump each screenful of large chunks onto the ground.

It takes a while to screen just one bag of bark. This isn’t something I’ll do for large amounts of material.

Finished material

This is a very loose potting mix. Water drains right through it. It likely holds very little nutrients. It definitely will not be soggy and will allow plenty of air to reach plant roots.

There are some longer pieces that made it through the screening holes. That’s a drawback with screening - long, narrow pieces can get through the screen. They are easy enough to pick out by hand if I don’t want them.

Use

I am using it for propagation of epiphytes and other similar tropical plants. In this case I am propagating a heart-leaf philodendron. This should also be good for orchids. I may also use it as an additive for other mixes.

Results

Hard to tell yet since I just started making and using this. I like it!

Later results

I used the bark to try to root philodendron cuttings. It seems like they took forever to develop roots. That was unexpected - I thought it would be quick. I’m wondering if there is an issue with the bark. I read about using bark in potting mix and it seems that it is usually aged or composted. That helps with the pH and breaks down some of the hydrophobic chemicals in the bark. So maybe fresh bark is not great. It seems commonly used for orchids, though.