growitall said:http://wildgingerfarm.com/BuildaTufaRockGarden.htm
The text to the photos above describes the planting mix as "a scree mix consisting of equal parts coarse sand and... crushed rock" but from the appearance of it (black colour), it's clear it's actually a humus-y soil* ... but whatever works in your area, given the climate and how much drainage you need to provide. Also, some plants prefer more more organic soil while some need very lean (little organic matter) substrates.
I used a rich mix, as in the tutorial above, in my first tufa garden, and have always felt it was too rich, promoting too much plant growth (I want plants to stay in character - small and tight, as they would be in nature) and restricting drainage... I went with a much leaner mix (an actual mix of sand and grit with very little soil) in the later beds that were added on.
plus some more awesome photos--Thank You
Yes, there is not one answer that fits all here because there are so many variables to consider, the most important being what a particular plant needs when that is the plant you are trying to grow.
(I acquired too many house plants because I had a friend who kept giving me plants that were fired (not dead but not happy) from the buildings he was contracted to care for--just because a plant tolerates low light and not being watered or watered too much doesn't mean they perform well for the duration, in the darkest corner of the office with inappropriate water regimes, for example.)
Anyway, some plants absolutely require a lean, free-draining mix, some prefer it, some behave better with it, and some can't live like that. And that is determined by the particular plant.
Climate and other environmental factors--temperature extremes, relative humidity, precipitation amount/type/frequency/seasonal variations, soil type and grade, etc., are all important considerations too. Some things we can manipulate--others not so much.
For me in the high desert it is undoubtedly different than for a2b1c3--I don't really have to do anything special to grow many cold-hardy cacti, but I don't grow them. (isn't it a classic thing to try the stuff that really wants to live somewhere else?)
Growitall has moved to leaner mixes...
I started with pure sand/grit (freaked out about the drainage issue), killed things when I could not water in the summer, and have moved to more soil in the mix...
Probably has everything to do with differences in what we are trying to grow and where we live.
