Re: gardening in the humid tropics of the Philippines.

i never tried charcoal and was always told to be careful with using too much ashes. best product i used was a Kelloggs "Compost" that was really more of a tiny woodchip/sawdust kind of product. i dont think it added much in the way of nutrients but it was great for soil structure in that it preventing clumping/hardpan, allowed excellent aeration, good moisture holding capacity and made it easy for plants to send roots deep into the soil. to this i added a regular type of compost (Supersoil), steer manure and blood meal, bone meal etc. i was able to get all this stuff from Home Depot, heheh.

unless you have a very large area of garden i dont think the original soil makes much difference as long as you can get the amendments. what about dairies as a source of manure? do they have rice straw avail there cheap? other agricultural by-products or waste products that have organic matter?

btw if most people are growing only those select few crops then it might be the case that insect pests for any other crops are not too prevalent and you might have success with those?