Screening

[flor1]

Decided to finally start screening my soil mix when I make a batch.
Shocked at how many fines I got guessing right around 15 to 20%.
The largest percentage from Lava rock by a large amount.
Turface not nearly as bad as I thought it would be.
Poultry grit the best as expected.
Will be screening everything from here on out.

 

[markyscott]

What hole diameter are you using on your mesh?

Scott

 

[flor1]

What hole diameter are you using on your mesh?

Scott

Window screen not sure on the diameter

 

[markyscott]

I think that standard window screen has about 1/32" hole diameter. That will retain a pretty small grain size component in your mix. If you're looking for a lot of water retention it should answer.

I tend to build less water-retentive substrates and water more frequently. My finest sieve has a 1/8" hole diameter - I discard anything that passes through that. I mix a fine-grained substrate that is 1/4"-1/8" that I use for more moisture loving plants and a 3/8"-1/4" for pretty much everything else. I've experimented with 1/2"-3/8" particle size also (juniper) and plants seem to do just fine in that also.

I understand that turface has some variability, but in the MVP I've worked with, 45% of the bag was discarded with the fines. Although 51% was suitable for the fine-grained substrate only 4% was usable for the general mix. That's why I've moved away from turface - it's too bad as the grains will hold a lot of intragranular water (more than akadama, for instance). It's a lot of work to eliminate the fines and there's a lot of waste product involved which increases the net cost for the size fraction I'm interested in.

Scott

 

[nathanbs]

you should consider screening out the next size up(1/16th" i think) as well as it certainly can cause your soil to hold way too much water. Ooops Markyscott typed faster than me. What he said. Anything above 1/4" for me in sunny so california can get dangerous. So anything bigger than that i only use as a drainage layer