Tuesday, March 3, 2009

Papayas a Plenty

How to grow papayas in your back yard.

Papayas are very easy to grow in Haiku due to a climate well suited to their needs. Papayas are originally from the tropical zones of Central and South America. The single stem trees grow very rapidly, and can begin to bear fruit in as little as 6 months.

Papayas are full of vitamins including vitamin A, vitamin C, potassium, calcium, iron, thiamine, riboflavin and niacin. Papayas are also low in calories, and are trumpeted as a good addition to a healthy diet. Papaya fruit is also converted into tablet form for sale as a remedy for digestive problems.

Papaya Space

One of the most important aspects of growing a healthy papaya tree is that the papaya has its own space. It is especially important that the papaya is not grown surrounded by grass or other ground cover.

The papaya likes well-drained soil, and should thus not be planted in an area where rain water tends to accumulate. Papayas have shallow roots and greatly benefit from the use of organic mulch (more on that later).

Papaya Sex

Papayas come in three sexes, male, female and bisexual (hermaphrodite - both sexes are present.). Only the females and the hermaphrodites produce fruit. In commercial production, papayas are typically planted with 4 or 5 trees per “square”. The squares are planted every 10 feet or so. The trees in each small group grows very rapidly. At several feet tall, the trees begin to produce small white flowers. These blooms allow the tree to be sexed. At that point, all the trees in each group are cut down except the largest hermaphrodite.

Determining which tree is the hermaphrodite is a bit of a trick. The difference in the flowers is rather subtle. Depending on where you get your seeds (or seedlings) the odds are very good that you will get either a hermaphrodite or female tree (due to selective breeding programs in Hawaii).

Planting a Papaya

One tree will usually produce enough papayas for one person to have papaya whenever they want. So you might use the number of avid papaya eaters in your family to determine how many trees to plant. Just be sure to space the trees about 10 feet apart to maximize the amount of sun they receive.

Papayas have a strong root system and can dig into hard soil quite well. However, there is a big difference between hard-packed red clay and “garden soil”. If your yard is more the former, then copious amounts of organic mulch will, over time, help to “soften” the soil (mostly thru worm action). A rototiller will greatly speed up the process, and mixing in compost will yield dramatic results.

Papayas are pretty easy to please. The following steps are a method I have used to produce healthy papaya trees and abundant fruit. As some trees produce more, some less, it might be a good idea to plant more than one.

When planting a papaya seedling:

1. A circular area with an 8 foot diameter (optimal) should be cleared of all vegetation. No tall trees or other structures should shade this area. A piece of 6-mil black plastic could be used to cover the ground and kill off any weeds or grass (remove the black plastic after 3-5 weeks and prior to planting your papaya). Alternatively, you could clear the ground with a hoe or shovel (etc).
2. Dig a hole 1-2 feet deep and 3 feet wide. The hole should be shaped like a saucer: deep at the center, but shallow at the edges. This will result in the best growth of your papaya, but less digging will work well too.
3. If the dirt you have extracted is very rocky and/or solid red clay, it would be a good idea to replace half of the dirt with a good garden soil (the best stuff being found at the bottom of your compost pile). Be sure to mix the replacement soil with the old soil to prevent layering.
4. Plant the papaya in the center and tamp lightly. Give it a good watering.
5. Lastly, place 4 inches of mulch over the entire 8 foot circle. Leave an inch of space between the mulch and the papaya seedling. Adding mulch is probably the most important step and also most often skipped. Papayas do fine without fertilizer, but will greatly benefit from the use of mulch.

The super-easy (seed) method:

1. This method works well given good soil and pre-existing much cover (i.e. a weed-free and grass-free environment that has been covered by mulch for at least 6 months). As above, you’ll need a sunny area. With this method, it’s best to dedicate 3-4 circles (where each circle is 8 feet in diameter – optimal).
2. Take the seeds out of a tasty papaya (should be a locally grown papaya). In the center of each of your circles, mix a dozen or two seeds in with the mulch (must be organic mulch – not lava cinders or man-made materials).
3. For the next two weeks, make sure the circles stay moist (2-3 rain showers per week should suffice!)
4. When the tallest papaya seedlings reach 10 inches or so, remove all but the tallest seedling. You may end up with a non-fruit bearing (male) tree, but if you plant several trees, the majority will be female or hermaphrodite.
5. Keep the area well mulched. If you can see the soil, it’s time to add more mulch (available for free at Ho’omaluhi Botanical Gardens and Hawaiian Earth Products in Kailua on Kapaa Quarry Road).

After planting, papayas need little care. Just re-top the mulch as necessary to keep weeds and grass away from the tree.

One note of caution about papayas. Un-ripened papaya fruit, when scratched, releases a latex fluid. This fluid can cause irritation and provoke allergic reaction in some people.

Papaya leaves also contain carpaine, an anthelmintic alkaloid which could be dangerous in high doses (so don’t feed the leaves to your livestock). Carpaine may also be present in immature fruit, although humans have been eating green papayas for generations.

A good time to pick your papayas is when you first see a hint of yellow on the fruit. The fruit will ripen off the tree within a day or two. If you would like to serve a large quantity of papaya at one time, you can pick the green fruit closest to the bottom of the tree. Place all the fruit in a plastic bag and the fruit will all ripen rapidly. Be careful to not let it over-ripen.

Papayas are probably one of the easiest and most productive fruit bearing organisms to grow in Haiku. If you give your papaya trees enough space and keep the ground well mulched, you will soon enjoy a continuously harvestable crop of papayas.

References and more information on Papayas:

Extension Horticulture Information Resource – Agriculture Program – Texas A&M University:

California Rare Fruit Growers

Alternative Medicine Online


Hall of Fame scientist noted for helping to save papaya industry

Free mulch on Oahu (list)

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