Maybe it was inevitable, but I have decided to go "dirt less" in favor of a largely inorganic potting mix for all or most of my "little trees".
From the start of this adventure, 'dirt' has played a pivotal role; First, just plain old generic potting soil seemed to work..then chlorosis (caused by overwatering) entered the fray & it was determined that I needed a mix that drained freely, with a "grittier" content & feel...enter Cactus & Succulent Mix, But as the collection grew & the number of species & cultivars multiplied, I found myself amending this "ideal" mix in order to neutralize pH, to add chelated iron to the soil, adding worm castings for a higher organic mix, adding perlite to lighten the soil, pine bark to lower pH.
The final straw, for me was soil compaction..we had about 6 weeks of unusually hot temperatures, this summer, which in itself presents unique problems for the container gardener. Plants in small containers, particularly plastic, can overheat in the direct sun & cook the roots; too much sun can wilt foliage, while at the same time promoting stellar growth in some candidates, but soil compaction can turn potting soil hard & impervious..water does not penetrate, but runs off before absorbtion, small feeder roots die first, making it even harder for the plant to feed itself.
An
inorganic potting mix comprised of inert compounds found in lava rock, pumice, fired-clay, decomposed granite, charcoal is used by bonsai growers in place of organic potting mix, made with composted peat, Pine Bark, leaf mold, manure or sometimes Coco coir.
When compaction occurs, there is no choice but to repot, which is traumatic for the tree & exposes the plant to damage from handling, possible contaminants on gloves, tools, buckets & for most of us, something of a "crap shoot" as to whether the repot will be successful or lead to the loss of the specimens.
The use of an inorganic mix will reduce the need to repot so often & allow re-use of the mix, which could actually save money in the long run.
