Soil
Background Information
Soil units
Materials exist in 3 parts relative to their volume:
% Water
% Air (gas porosity)
% Solid matter = 1 - water - air
Soil levels
The saturated water limit is referred to as field capacity.
Boon's bonsai mix
Field capacity 0.23
Gas porosity 0.37
Sandy loam
Field capacity 0.20
Gas porosity 0.18
Potting Soil
Field capacity 0.37
Gas porosity 0.08
Species Info
The lower limit of water is referred to as permanent wilting point. This is the point where the tree dies.
Jeffrey pine in sandy loam
Water: 0.053
Ponderosa pine in sandy loam
Water: 0.064
White fir in sandy loam
Water: 0.068
Tomatoes in sandy loam
Water: 0.103
Calculator
Method
Testing was done using clear 9 fluid oz dixie cups. Holes were drilled into the bottom for good drainage.
Substrates packed down to the 8 oz line. Note: No compaction or expansion occurred even after wetting except in the potting soil.
Dry weight measurements taken. Note: Dry weight also taken again at end.
Containers submerged for 10 hours to fully wet the substrates.
Containers removed and water allowed to drain until only a small amount of perched water remained.
Drained water weighed for porosity calculation (air capacity = drained water).
Wet soil weighed for field capacity calculation (water capacity = wet soil - dry soil).
Cups placed outside on the concrete at 10AM. This was around September in Zone 11a with temperatures reaching 95F and 30% humidity.
Weight measurements taken at hours 0,1,2,3,6,12,24,48,72.
At the end of 72 hours the substrates were microwaved to remove any remaining moisture. Dry weight measurements were again verified.
Notes
Weight measurements taken on a food scale accurate to 1 gram.
Due to the size difference of grit, sand, and potting soil; those substrates are not included as options for the calculator.
References
Inspiration
Brian Heltsley. "Water Retention and Drainage in Bonsai Soil". The Journal of the American Bonsai Society vol_48
http://fingerlakesbonsai.weebly.com/bonsai-info.htmlBonsai Jack. 2014. "Bonsai Soil Aggregate Test Report"
http://www.bonsaijack.com/BonsaiJack_Bonsao_Soil_Aggregate_Report_2014.htmlBob Hale. 2015. "Soil: It's What Goes in the Pot". San Diego Bonsai Club
http://www.sandiegobonsaiclub.com/soil-its-what-goes-in-the-pot.htmlBackground Information
Units
Argonne National Laboratory Environmental Science Division. Porosity
http://web.ead.anl.gov/resrad/datacoll/porosity.htmSoil Levels
Brian Heltsley. "Tuning Soil Recipes for Water Retention and Drainage". The Journal of the American Bonsai Society vol_49
http://fingerlakesbonsai.weebly.com/bonsai-info.htmlCompetency Area 2: Soil hydrology AEM
https://nrcca.cals.cornell.edu/soil/CA2/CA0212.1-3.phpSoil type determination guidelines
http://www.pstif.org/apps/soil%20type%20determination%20guidelines-3.pdfSpecies Info
E. C. Stone. October 1957. "Coniferous Seedling Survival". CALIFORNIA AGRICULTURE vol 11 issue 10
calag.ucanr.edu/Archive/?article=ca.v011n10p7Hendrickson, A. H., & Veihmeyer, F. J. (1945). PERMANENT WILTING PERCENTAGES OF SOILS OBTAINED FROM FIELD AND LABORATORY TRIALS. Plant Physiology, 20(4), 517–539.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC437248/Calculator
Diatomaceous Earth
1/8 inch Diatomaceous Earth. Water content 0.261 oz/in³ or field capacity 45%.
Turface
1/8 inch Turface MVP. Water content 0.176 oz/in³ or field capacity 30%.
Akadama
1/8 inch sun-dried Akadama. Water content 0.200 oz/in³ or field capacity 35%.
Orchid Bark
Sifting between 1/16 inch and 1/4 inch didn't work due to the odd sizing. Diameter roughly 1/8 inch. Water content 0.093 oz/in³ or field capacity 16%.
Perlite
1/8 inch Perlite. Sifted between 1/16 inch sieve and 1/4 inch sieve. Water content 0.095 oz/in³ or field capacity 17%.
Red Lava
1/8 inch Red Lava. Water content 0.103 oz/in³ or field capacity 18%.
Granite Grit
From source unknown Decomposed Granite/ River Sand. Sifted between 1/16 inch sieve and 1/4 inch sieve. Most particles were nearly 1/16 inch. Water content 0.032 oz/in³ or field capacity 12%.
Potting Soil
Fresh potting soil with little to no sticks. Made from at least 45% peat. Water content 0.215 oz/in³ or field capacity 37%.
River Sand
A sand grain size used in bonsai referred to as river sand. Water content 0.193 oz/in³ or field capacity 33%.
