Adapted from The Herb Companion

The subtle-hued, many-textured gray and green herbs native to the Mediterranean are favorites in the herb garden. In their homeland, lavender, marjoram, oregano, rosemary, sage, santolina, savory and thyme cling to chalky cliffs and hillsides and stubbornly exist in barren, dry, sandy, rocky soils. But in our gardens in Maryland (Susan) and Arkansas (Tina Marie), we’ve proved that these Mediterranean immigrants do just fine on American soil with a few amendments. We re-created a Mediterranean region for these plants in our gardens.

Full article here

(I think that the methods described within can be extrapolated to Singapore’s climate as well).