Thanks Don - I’ve been hearing something similar.
Been trying to figure out the best balance of adding nutrient to the soil, while setting up the roots for success (in the form of growing past the original 60 gallon hole, as figs are said to grow ~10 feet deep and ~10 feet outwards).
Some say 50/50 mix of native soil to my own soil mix.
Some say 100% native soil.
Some say maximum 5% organic matter, mixed in with native soil (as stated in the paper linked by Vlad).
I’m all for nature doing it’s thing, and coming from no-till container growing, my inclination is to add as much organic amendments possible. But maybe 100% native soil, and just top dressing would be ideal. Still trying to figure that out - the ideal ratio of organic matter to the native soil (if any).
I don’t know much about soil microbiology, but I know it’s important. I have a organic worm bin, which I feed organic scraps and organic amendments to (ie. kelp, crab meal, malted barley, oyster shell powder, basalt, etc). That should add some good microbiology as well, no? (Those worm castings).
Right now my idea is to fill the 60 gallon backhole with:
- 5% organic matter (1 gallons bu’s blend compost, 1 gallon worm castings, and 1 gallon peat moss = 3 gallons total)
- 2 gallons of pumice
That would be 5 gallons of additives into the 60 gallon hole (8.33% additives), however only 5% of the additives would be organic matter (the compost, worm castings, and peat moss).
I also was told it could be good to create a 6" raised big flat plateau above ground level, and make that 70% native soil to 30% of my soil mix (40/40/20 of pumice / peat moss / compost).
How’s that plan sound to you guys?
(Or would it make 0 difference, and just plant into native soil, just top dressing with my worm castings?).
Ideally I would dig 2 holes and test it out, but I don’t have room for that.
Thanks for any suggestions!