What is the best planting mix?

[imafan26]

We have mostly sunny days with light rain. A bad day is when it rains all day.
Most of the rain falls on the windward sides of all the islands and in the mountains. The Koolau's get 200 inches of rain a year, so that is where most of our water comes from.
I live in the high central plain created by lava from the two main volcanoes that created the island. It is cooler than the lowlands and relatively wet compared to the dry leeward side.
Except for the garden near sea level, the other plots drain well and subside in a few hours even after flooding rain.
The garden at sea level is in a flood zone and will stay flooded for days. I think I might do more research on hugelkultur. There are logs, tree trimmings, and compost available at that garden to make it work.

[digitS']

Semi-arid conditions on a tropical island where mountains catch an enormous amount of the rainfall !! The Koolau Range on Oahu is there in dark blue:


Giambelluca, T.W., Q. Chen, A.G. Frazier, J.P. Price, Y.-L. Chen, P.-S. Chu, J.K. Eischeid, and D.M. Delparte, 2012: Online Rainfall Atlas of Hawai‘i. Bull. Amer. Meteor. Soc., doi: 10.1175/BAMS-D-11-00228.1.

I garden in a semi-arid location with less than 20" of precipitation each year but much of that falls as winter snow . . .

Interesting contrast & similarity

Steve

[imafan26]

It actually is not that arid. There is a marked difference between the green and lush windward side and the dry leeward side. Most of the wild plants, have adapted, they will dry and look almost dead but will green up with just one good rain.
I just realized a problem with Hugelkultur. Termites! Buried wood is an open invitation and they will also eat woody plants and sweet potatoes.
Most native tropical cultures just cut down a part of the forest for crops. When the land was no longer productive and nearby resources became scarce, they moved to another part of the forest. Composting was done by the forest. They did not have metal tools until after the western ships arrived to cut down large trees. Plantations learned the hard way that native trees don't come back after being cut. When the rains came the soil washed away.
Wherever you garden, you need to take into account practices that are in harmony with the whole ecosystem.