Khalid Waleed (zone 9b Isb)

Straw wrote: "EarthCo. is a professional soil-testing company. They stated: "The amount of organic matter in garden soil should be between 2% and 5%. Levels in excess of 10% should be avoided. Soil that are too high in under-decomposed organic matter consume nitrogen away from plants during decomposition. Also increases the potential of excessively wet soils that reduce plant growth."

Straw: I can fully understand that un-decomposed or under-decomposed organic matter consumes nitrogen hence 2 to 5% organic matter. But what if the organic matter is fully decomposed? The figure for 2 to 5% and not more than 10% applies for fully decomposed organic matter too?

I have seen plants growing excellently in jungles and in jungles, the top many inches of soil is actually over 90% organic matter, ie, decomposed leaves and other other organic matters. Your views.

*** From Straw: In a warm zone, trees don't lose all their leaves like cold zone. Here in my zone 5a, the soil in the woody-area are caked with wet leaves falling all at once The climate here is too wet and too cold for leaves to decompose .. in spring time, we still have wet & under-decomposed leaves which suppress weeds & plants.

In your warm zone 9b, there's less leaves falling down, plus warmer weather to give leaves plenty of time to decompose completely to fluffy & black organic matter (humus), which is very good for plants' growth.

Below is a pic. of snapdragron self-seed themselves in my garden yearly, but THAT DID NOT HAPPEN LAST YEAR WHEN I DUMPED TONS OF LEAVES AROUND ROSES. And roses still died last winter due to poor drainage & excessive rain & freezing temp. Now I dump leaves around trees only, to kill weeds & all plants.

Below is at least 12 inch. or 0.3 meter of leaves, it's soaking wet underneath. I dumped leaves there so Russian Sage can't sucker. Russian Sage likes it dry, and declines when it's too wet. Lowest is tomato still green on Nov. 11, the day before freezing: