I could not say for definite where things are going wrong with your seed sowing most things will germinate in just about any medium even damp kitchen roll, seeds should be stored at a cool temp I keep my extra seed in an airtight container in the fridge, now if they are germinating and then not progressing that could also be down to heat stress. If I was to build raised beds I would use CHB's and build them close to the height of a Kitchen countertop, It goes without saying all areas should be in reach without bending too far, likely it will be your partner that is attending to these so her furthest reach should be considered, the bottom third of the bed, should be filled with rubble and drainage holes must be provided at the very bottom as you do not want a tank that gets waterlogged. You will be aware of the portable Gazebos/ Canopy's that are in use there, this is how I would have my frame built, may I suggest you get a hold of German Peter he knows a couple of Pinoys him and I trained them both, you cannot make a Silk purse out of a Sows Ear but they are better than average, they are employed 6 days a week but may be able to work Sundays, one is actually working for Peter and likely he would stop his job for day or so to get you going, failing that wait till I come over, one of these guys is good at welding with a Flux core mig he will do a far superior job than anyone with a stick welder. The site for this should not be close to a wall it is already shaded on both the roof and south side, too much shading gives long leggy growth and the plants just keel over. Top soil is readily available there and a truck load of 3.5 cube is around P2K, sand is about the same price but only around 10% is required to mix with the soil. There you have it most of your problems solved.
Thank you, Sir. I'll appreciate your advice. It is a hzfe help for me to ket me participate of your sound knowledge of gardening. Anyhow, come over and let's have a few beers. It would give me a particularly pleasure. Thank you.
OK we can do that I do like a Beer or two. I do have lots of experience growing veg in UK but none in PH, but know the shading works, even in UK direct sunlight at the hottest part of the day is not good for them, one time my partner had grown Veg plants in a heavily shaded area under a large tree canopy where they only had direct sunlight early morning and late evening, this was a great success for her.