nico239 wrote:... You can always try to leave a corner where you do nothing: remove the pebbles or upgrade and compare ....
This comparison, I can do it! It was completely unintentional at first, it is not in the kitchen garden but whatever, the comparison can be made.
There are 3 years I planted a hundred iris. I first put eighty along a wall, in a soil that was sifted to a thickness of about 40 cm. The rest on a mound where the earth has not been sifted but simply cleared of the largest pebbles.
I put a handful of compost at the planting of each rhizome.
Photo of the irises planted along the wall in a thickness of 40 cm of sieved earth:
- Iris in sieved earth .jpg (302.7 Kio) Viewed 2795 times
Photo of the irises planted on the mound of "raw" earth, soil which is already better than the original soil:
- Iris in rough earth.jpg (380.49 Kio) Viewed 2796 times
The smartphone gives the scale.
Irises planted in the mound of raw earth never bloomed. They are 3 at 4 times less high.
There's no picture ...
To each his way of doing things.