There are 2 problems with growing Marang 1) insufficient or no pollination, as sometimes you can get fruits totally empty of pulp inside 2) good pollination but very few fruits on the tree. I have the second problem. I think this is probably due to seedling variation. There might also be a problem with self incompatibility in some cases so plant at least two trees side by side. I have a friend that has Marangs which are consistent bearers, good pollination and often have 2 crops. The thing to do would be to graft from those trees. If you don't have good marang scion wood available in your area suggest planting as many seeds as possible and culling the bad ones out. As far as I know only in the Phillippines do grafted Marangs exist and even there I think grafting of this fruit is very limited. This is a really excellent fruits, but obviously it needs some more development. Ref: Oscar – Hawaii Sheryl: One of our members is growing Marang down the Gold Coast – has flowers but doesn't set.
Marang and a lot of the tropicals like a deep well drained soil is the most important. In the beginning I just made the planting holes about 50 cm deep and a lot of my plants stay small. Now I make the holes more than 1 metre deep and there’s a big difference in growth. I was almost considering growing it on a mounded pile of dirt here - again, problems with soil stagnation. Ref: Luc in Mexico
I visited several commercial Marang farms in Mindanao and the taste has not much to do with the kind of seedling in my opinion but much more with fertilizing. Those farms who fertilize copiously with Muriate of Potash after fruit setting seems to produce much sweeter Marang with bigger pulp portions then those who are not well fertilized. Ref: Will