Last updated: 25 August 2016
I have always experimented with soil mixes -- I believe I have used just about every one that has been devised during my growing lifetime -- and I have found all those that were of coarse and gritty texture, thus providing excellent drainage and root aeration, contributed significantly to growing healthy and robust plants.
A great thing about being retired -- and old -- is that you have the time to do all the fun things you always wanted to do but, for one reason or another, couldn't when you were younger. I have always wanted to experiment using native desert soil (and desert humus) to grow cacti in containers. I make no claim for the soil mix I feature here as to whether it will grow healthier and more robust plants. The experiment is strictly unscientific. I just like the look and feel -- the light brown color and gritty texture -- of this soil mix.
Glossary for this web page
Cactus habitat photos
The following photos show typical Tucson area Xerophytic landscapes and vegetation -- Saguaro (Carnegiea gigantea), Ferocactus wislizenii, Opuntia engelmannii, Cylindropuntia fulgida, Cylindropuntia versicolor, Mammillaria microcarpa, Velvet Mesquite trees, Creosote bushes, bursage, desert bunch grasses, various desert shrubs and scattered organic debris, etc.
Velvet mesquite is one of the most common, and important trees of the Sonoran desert. It is useful to humans and essential to the survival of wildlife. Birds, insects, and mammals eat the beans, seek shelter under its canopy, and benefit from the leaf litter and nutrient rich soil beneath it.
Scattered organic debris -- juvenile Saguaro in foreground
Cylindropuntia fulgida, Cylindropuntia versicolor,
creosote bush, ragweed and other small Xerophytic plants.
Velvet Mesquite tree, Saguaros, Ferocactus wislizenii,
creosote bush and various small Xerophytic plants
Mammillaria microcarpa and scattered organic debris
Opuntia engelmannii, Saguaro, creosote bush,
bursage and other small Xerophytic plants
Recently fallen Velvet Mesquite Bean pods
Tucson area cactus habitat soils
Our Tucson area cactus habitat soils are very sandy and gritty and frequently contain substantial amounts of fine dust. They contain very little organic material due to the paucity of ground cover vegetation.
The Cryptobiotic soil crust is an important source of nutrients. Our native moss tolerates very harsh desert conditions. It survives dehydration, extreme heat, and freezing. When it rains it quickly rejuvenates and immediately starts to supply nutrients to the soil.
Habitat soil components
Top soil with scattered pieces of Cryptobiotic soil crust.
The soil is sandy & gritty with substantial amounts of fine dust.
Desert humus scraped off the top of the soil under native Velvet
Mesquite trees. It mostly consists of decomposed leaves, bean
pods & sclerophyllous plant parts including roots, stems, twigs
and floral remains.
Constituency of my Sonoran Desert Cactus soil mix
Mixed Sonoran Desert Cactus soil
Old Johnson Cactus Garden Catalog excerpt
In Johnson Cactus Garden (Paramount, Calif.) 1963 Catalog.
I think their cactus leaf mold was similar to my desert humus.