Last year I remodeled the dirt, so I don't know what depth it came from, might have been a few feet.
Discussion
what are you growing btw?? anything exciting?
I started growing first time last year. I had herbs like thymes, basil, persil, chives, all great, and all but the basil lasted through harsh alpine winter. Lettuce, tomatoes, carrots, cucumbers, zucchinis, pumpkins. Lettuce and pumpkins were great, the rest was horrible.
So this year I'm applying the pareto principle, 80% greatness for 20% of the work. I've got lettuce and pumpkins for the win. And I added more herbs, got the finest big bushy rosemary from Catalan.