Papaya

What is a papaya?

The papaya looks like a small palm: a slender, usually unbranched stem marked with the scars of fallen leaves, topped by a crown of large, deeply lobed leaves on long, hollow stalks. The fruit hangs directly from the stem beneath the leaves, often in dense clusters. Yet it is neither a palm nor a true tree. Its stem is soft and barely woody, it grows with astonishing speed, and a plant in cultivation is productive for only a few years.

Origin and growth

The papaya probably comes from southern Mexico and neighbouring Central America. Spanish seafarers spread it early: it reached Panama and the Caribbean before 1525 and the Philippines around 1550. Today it is grown throughout the tropics.

A papaya can reach 10 metres, but in cultivation it is usually renewed long before that. Under good conditions it flowers about four months after planting and bears its first fruit after seven to eleven months. Papaya plants are male, female or hermaphrodite. Only female and hermaphrodite plants normally bear fruit; female plants need pollen from a male or hermaphrodite neighbour.

Requirements

Warmth. The papaya is very frost-sensitive. Below about -0.6 °C it is damaged or killed; below 15 °C flowering suffers and fruit can be misshapen.

Water. It needs plenty of water, but soil that stays wet kills it quickly. According to Morton, 48 hours of flooding is fatal.

Soil. Loose, well drained and rich in organic matter. In wetter places it is planted on a mound.

Light and wind. Full sun and shelter from wind, which tears the large leaves and can topple the shallow-rooted stem.

Fruit, use and harvest

Ripe papayas are eaten fresh; green fruit is cooked as a vegetable in many tropical cuisines. The plant contains a white latex in its stem, leaves and unripe fruit that irritates the skin, and the papain it contains can cause allergies. Gloves are advisable during harvest. Leaves contain carpaine, an alkaloid that acts on the heart and is destroyed by heat. Unripe fruit and seeds should not be experimented with; Morton reports their hazardous use to induce abortion.

In the food forest

In a food forest the papaya is a plant of the first years. It grows fast, gives fruit early and casts light shade over young trees, then gives way after a few seasons. In syntropic agriculture such short-lived, fast plants fill the space the long-lived trees will later occupy. When a papaya is cut, its soft stem and leaves decompose quickly and return to the soil as mulch. As a pioneer it is valued for speed, not permanence.

In the Mediterranean climate

In Mediterranean Europe papaya is mostly grown under cover. In the Canary Islands the area rose from 122 hectares in 2000 to about 378 hectares in 2014, almost 93 percent of it in greenhouses, mainly because the papaya ringspot virus, spread by aphids, devastates open-air plantings there; greenhouses also shield the plants from wind and winter cold. In Almería and Granada a few dozen hectares grow in greenhouses, and in Sicily too papaya is grown under cover. Open-air plantings on the Mediterranean coast are rare and depend on very warm, sheltered spots.

For colder sites Morton mentions the mountain papaya, a relative from the Andes that is grown in climates too cold for the true papaya. The papaya is not on the EU list of invasive alien species.

Propagation and care

Papayas are grown from seed, which germinates readily when fresh. Because the sex only shows at flowering, several seedlings are often planted together and thinned later to the fruiting plants. Young plants need protection from cold and wind and an airy, well-drained soil covered with mulch. In regions with virus pressure, plantings are renewed every two years or so.

How Terra Humana understands it

At Sa Medada the papaya is a short-lived guest with a clear task: to grow fast, to show early what a warm spot on the slope can carry, and to give its biomass back to the soil when its time is over. That it grows in the open ground, where in Mediterranean Europe it is usually kept under glass, makes each of its seasons informative.