I will start my own farm soon. If you want good source of information I have one link in a footer of my graviolafarm webwite
soursopfarmthailand dot org.
Follow the link our from my page and read especially the pdf -files in that graviola page. And if you are happy for this advice please come back to my website and lease one tree from me for five years. You will have the leaves harvest from years four and five which maybe max 200 bags = 200 months amount of tea.