Believe me, we have now been living for over ten years in Panama and we still have not managed to grow a papaya tree, so we are experts in this matter.
The most important rule for not growing a papaya is to buy saplings in a nursery and then transplant them. Your nursery –owner will tell you that nothing is easier than growing papayas, and they are wrong. Transplanting invariably kills the papaya plant. Dying may take anything from two days to almost half a year, but die they will. The good thing is that you have spent money and put in an effort and still are empty-handed, papaya-wise. But the owner of your local nursery will love you and encourage you to try again. The nursery-owner will give you some fool-proof tips to keep your papaya trees alive, knowing that they will die anyway. But a little later, so you will probably be back for more. In our opinion, nurseries that sell papaya saplings are not much above your local drugs pusher.
Another good rule to be successful at not growing papaya is to not take care of them. Lots of people will tell you that papaya trees are naturally resistant against just about anything. This is a lie. Rest assured that just about every caterpillar, aphid and grasshopper plus a couple of fungi with unpronounceable names that live in your garden, will love to dine (and lunch and breakfast) on your papaya tree. In the unlikely event that your papaya tree develops more than two leaves, the caterpillars will eat them. Should the stem of your papaya tree reach 5 cm diameter, stem-borers (a special group of caterpillars that lives in the stems of plants and trees such as maize (corn) and papaya) will hollow it out and your tree will die.
People will tell you that papayas prefer good soils and lots of water, but will basically grow anywhere. This is not true. Papayas will grow anywhere you do not want them to grow. And never where you plant them. Planting the tree just about anywhere and then trying to save it by fertilizing is a good way to let your papaya tree die. And this method also has the added advantage that you spend money on fertilizer and effort on working the fertilizer into the soil without getting an actual live papaya tree.
In the unlikely event that some of your trees survive, do not worry too much. You will most probably find out that all the survivors are male, which means that you will get no papayas whatsoever. Believe us, the best way to get a papaya is to buy it from your neighbour or in a supermarket.