Papaya Planting - Tips For Seed Variety Selection, Germinating, Growing, and Harvesting
I have a few tips for papaya production.
First of all, it's best to have a variety that you consider tasty. Why waste your time planting something whose taste you do not like? One way to do this is when you find some papayas that you like, find out the variety from the grower, and plant the same seeds. Buy them from a reputable source if it is not too inconvenient - like the University of Hawaii Seed Program (But some of the seeds by mail order before your next visit to the states, and bring them back with you on the plane, just don't mention it at the agricultural inspections. By the way, I also recommend buying some of their other seeds like pole beans and sweet corn from that same source.)
Of course, if you like the criollo (local) varieties, that makes it easier to get your seeds. You may also find some hawaiian-style (small and sweet) papayas locally and take the seeds out of the fruit. The resulting fruits may not be true to form (they may have hybridized with local varieties) but often the resulting fruit is not too disappointing.
Germinating papaya takes two to four weeks. Germinate in any soil mix with moderate humidity and drain holes to allow excess water to seep out the bottom. You might want to read some tips on papaya germination. Small papaya plants less than 2 inches tall can be easily transplanted brutally, but larger plants should not be manhandled. I recommend that when your plants are 1-2 inches tall, you make sure they are in large soil bags - leave 2-3 plants in each bag to grow together. Make sure there is some organic and/or chemical fertilizer in your soil. Give ample sunlight and water.
One to two months later, when the plants are about one foot high, plant them in rows, each bag about eight feet apart from one another. Hopefully each bag still contains 2-3 live papaya plants. If one looks sickly, just cut it off dead. To plant them, dig an extra-big hole, and add some chemical or organic fertilizer, then add some soil, put in your plant, add more soil. Ideally your hole will be big enough so that even after planting the plant, the plant is still in a dip. This makes it easy to water. (By the way, plant papayas in well-drained soils: they do not do well in boggy soil.)
Later your plants should begin to make fruit. You'll see that some flowers are male and some are female. Some plants (hawaiian varieties) have both male and female on the same plant. Others have only male or only female. If your plants have only male, they will never produce any fruit. If they have only female, they need cross-pollination from a nearby male plant. At this point when you see the first flowers, you need to use your common sense to eliminate the weaker plants, especially if they are extra males. One male-flowered plant can cross-pollinate a dozen female plants. Your goal is to cut back the unnecessary or weak plants, so that you are left with one plant per hole - the strongest, and usually female or dual-sex plants (leaving just a few males).
When the fruits begin to form, they will form from the female flowers (no surprise there!). In most tropical areas, you will have to take preventative action to avoid total crop loss from the papaya fruit fly, a ubiquitous and unmerciful insect.
Unless you are very lucky and don't have many of these around, you'll see the papayas get a drip mark on them, which is the sign that the papaya fly has put its egg inside, then when the papaya is still 1 -3 inches in size and green, it will fall off and never ripen. So you need to avoid this. One organic method is bagging with plastic or newspaper. The following excerpt is from the link about the papaya fruit fly above:
Bagging can be an effective control measure for the fruit fly in small plantings (one to 25 plants or less than 1/10 hectare). Bagging should begin when the fruit is small, shortly after the flowers have fallen off. Each fruit should be enclosed in a paper bag or rolled tube of newspaper and tied around the stem. This method can be very practical and successful if enough labor is available. Attention to covering new fruit and increasing the covering as the fruits increase in size is necessary.
Sanitation is also quite important in the control of the papaya fruit fly. All dropped and prematurely ripe fruit, as well as infested young fruit, must be destroyed in order to prevent the larvae from developing into adults.
You can also choose to spray your papayas with cipermetrina or something similar like deltamethrin. Both of these are low-toxicity insecticides that you as a home gardner in the tropics can learn how to use. They are based on the same basic compounds as lice and scabies medicine and are rather toxic to many insects but have very low toxicity for humans and most pets.
You can allow your fruits to ripen on the plant, or you can pick them when they first have some yellow color. As long as the fruit has some yellow color when you pick it, it will ripen and be sweet. Don't pick green fruit before it has any yellow color.
Most tropical soils are low in nitrogen, so this should be one of the main things you apply at planting time and again once per month. Urea is the simplest nitrogen fertilizer (put one teaspoon into a small hole about one foot away from the plant base on 2-3 sides of the plant). Your soil may also benefit from complete fertilizer and all soils appreciate organic fertilizer like compost as well. Once you have mastered the basics, be a scientist with your garden: apply one kind of fertilizer to a few plants, and another fertilizer to another few plants, and no fertilizer to another few plants. You'll learn in a few years what your favorite varieties require in your particular area, and that makes for more productive, delicious fruits, and better use of time and resources.