Sweet potato cultivation in Polynesia facts for kids
Sweet potato farming in Polynesia started around 1000 AD in the central Pacific islands. This amazing plant quickly became a key food source across the region. It was especially important in places like Hawaii, Easter Island, and New Zealand, where it became a main part of people's diets. By the 1600s, in central Polynesia, new, stronger types of sweet potatoes from the Americas began to replace the older, local kinds. This change happened a bit later in New Zealand, in the early 1800s. Even today, many of the old, traditional sweet potato types are still grown, but they are quite rare and not usually sold in big stores.
It's a bit of a mystery how sweet potatoes first arrived in the Pacific. Most experts today believe that Polynesians sailed to South America and brought the plant back. However, some studies of old sweet potato types suggest the plant might have reached Polynesia naturally, even before people settled there.
How Sweet Potatoes Traveled
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The sweet potato plant (Ipomoea batatas) originally came from the Americas. People there started growing it as a food crop around 2500 BC in Central and South America. It's believed that sweet potatoes were first grown as food in central Polynesia between 1000 and 1100 AD. The oldest proof found is from Mangaia in the Cook Islands, dating back to this time.
Over the next few centuries, sweet potatoes spread far and wide across the Polynesian Triangle. This includes places like Easter Island, Hawaii, and New Zealand. Sweet potatoes might have spread so quickly because Polynesian gardeners saw them as better than other plants they already grew, like the purple yam. The plant was likely shared between islands using vine cuttings, not seeds.
A popular idea about sweet potato types in Polynesia is the "tripartite hypothesis." This suggests that an original type of sweet potato, called kumara, came from South America around 1000 AD. Later, around 1500 AD, two new types arrived from Spanish and Portuguese ships. These were the camote type from Central America and the batata type from the Caribbean. Sweet potatoes became a very important food, especially in places like Hawaii, Easter Island, and New Zealand, more so than in central Polynesia. By the 1600s, traditional Polynesian sweet potato types started to be replaced by North American ones.
How Sweet Potatoes Reached Polynesia
The presence of sweet potatoes in the Pacific is often seen as proof that Polynesians and Native Americans had some contact before Christopher Columbus. But we don't know if Polynesians sailed to South America, or if South Americans visited eastern Polynesian islands like Rapa Nui. It's also possible the plant traveled without human help, perhaps floating across the ocean.
Some scientists have looked for links between Polynesian and Native American people. They've studied genetics, culture, and language. For example, some Dutch language experts think the word for sweet potato is similar in Polynesian languages and South American languages. The Proto-Polynesian word kumala (like kumara in Rapa Nui, ‘uala in Hawaiian, and kūmara in Māori) might be linked to the Quechua and Aymara words k'umar or k'umara. This similarity could mean there was some contact between the Andes mountains in South America and Polynesia.
Some researchers also suggest that sweet potatoes might have been in Polynesia thousands of years before humans arrived. They think the plants could have been carried by birds or floated on natural rafts. However, most experts still believe in the idea of human contact because of the strong language evidence.
Sweet Potatoes in Different Islands
Hawaii's Sweet Potato Story
On the Hawaiian Islands, the first signs of sweet potatoes (‘uala) are from around 1300 AD. Traces were found on old farms in Kohala, Hawaii. Sweet potatoes probably arrived after the first Polynesian settlers had already moved to the islands. People thought sweet potatoes were not as valuable as taro, another crop. But sweet potatoes were still widely grown because they could grow well in tougher conditions. They also took only three to six months to be ready for harvest.
Traditional sweet potato gardens in Hawaii were often in rocky, coastal areas. Farmers often planted sugarcane rows to protect the sweet potatoes from wind. Sweet potatoes were usually planted in mounds, with soil mixed with rocks and plants. Rats and insects like caterpillars and weevils could damage the crops. Sweet potatoes were also important for the New Year festival, Makahiki. The first harvest was offered to the gods.
By the mid-1800s, traditional sweet potato farming in Hawaii stopped. This was due to fewer people and damage from animals brought by Westerners. In the 1900s, new pests arrived, making it harder to grow sweet potatoes. Farmers often avoided planting sweet potatoes in the same spot year after year. Sweet potatoes became a big export for Hawaii in the 20th century, but the number of farms has gone down since the 1990s.
There are over 300 different names for traditional sweet potato types in Hawaii. Many names might be for the same types. Some common ones include apo, huamoa, kawelo, likolehua, and uahi-a-pele. Huamoa is described as egg-like, with white skin and yellow flesh. Most sweet potatoes grown in Hawaii today are newer types, like the Okinawa purple. But some old types, like lanikeha, mohihi, and purple kahanu, are still grown.
Easter Island's Sweet Potato Story
Sweet potatoes (kumara) arrived on Easter Island (Rapa Nui) around 1200–1300 AD. This crop was very good because it could handle dry weather. It replaced yam and taro as the main food on the island. Sweet potatoes were grown on about one-tenth of all the land. An old Rapa Nui story says that Hotu Matuꞌa, the first settler, planted sweet potatoes, yams, and bottle gourds near Orongo.
Some people think that sweet potatoes helped the islanders build the famous ahu platforms and moai statues. Big harvests meant people had more time for other activities, not just farming. Growing sweet potatoes might also have led to the cutting down of trees on Easter Island. Burnt palm forests provided nutrients for sweet potatoes in poor soil.
On Easter Island, sweet potatoes are usually planted twice a year, from January to April and August to September. Traditional Rapa Nui gardeners mixed rocks into the soil to keep moisture in the sweet potato fields. Plants are grown from cuttings and take 120 to 180 days to grow. Sweet potatoes were usually eaten right after harvest. Sometimes, they were stored for festivals by drying large tubers in the sun and burying them for up to a month. Sweet potatoes were eaten raw or cooked. The young leaves of the plant were also eaten.
New Zealand's Sweet Potato Story
Sweet potato (called kūmara by Māori people) is a traditional crop in New Zealand. Evidence suggests that kūmara arrived in New Zealand after the first Polynesian travelers settled there, probably between 1300 and 1400. Old stories tell of a trip back to central Polynesia to bring the plant to New Zealand. Many different canoes are linked to bringing kūmara, showing how important it was.
In 1880, a botanist named William Colenso listed 48 different types of kūmara grown in New Zealand. These old types came in many colors (red, purple, white), shapes, and textures. Kūmara does not produce seeds in New Zealand because of the climate. This means new types likely came from changes in the plant's buds and careful farming. A 1955–1959 survey found four types believed to be from before Europeans arrived: taputini, houhere, rekamaroa, and hutihuti. A DNA study in 1997 confirmed that taputini, rekamaroa, and hutihuti are indeed very old types.
How Kūmara Was Grown and Used
Traditional Cultivation
Māori people changed how they grew kūmara for New Zealand's climate. They learned to grow new plants from the tubers (the sweet potato itself) instead of from shoots. They also learned to store kūmara over the winter and grow it in the summer. Kūmara and hue (bottle gourds) could be grown on about 45% of New Zealand's land. This was much more than other Polynesian crops like taro. South of Taranaki and Hawke's Bay, kūmara was the most important Polynesian crop. In the South Island, kūmara was grown as far south as Banks Peninsula. Māori even grew kūmara in Otago in the 1450s, but farming stopped there before Europeans arrived. This might have been due to climate changes or conflicts. Kūmara roots can rot if temperatures fall below 10°C, but Māori might have used fires and heated rocks to help.
In spring, the flowering of the kōwhai tree and the call of the shining bronze cuckoo told Māori when to get their kūmara fields ready. Planting time changed each year, depending on whether a cold winter was expected. The stars and when kūmara leaves started to wilt in autumn signaled harvest time. Māra kūmara (sweet potato gardens) had puke (soil mounds) arranged in rows. These gardens could only be used for a short time before the soil lost too many nutrients. Māori used crop rotation, growing kūmara for 2–3 years, then burning the land and letting it rest. Light, sandy, or volcanic soils were best for growing kūmara. Gardens were often on slanted, north-facing land, which was drier and protected from cold winds. Sometimes, layers of beach sand, cut grass, and gravel were used for planting.
Pūkeko birds and hawk-moth caterpillars often ate young kūmara plants. To stop this, fences were built, caterpillars were removed by hand or smoked out, and tamed seagulls were encouraged to eat them. Younger plants were also eaten by kiore (Polynesian rats), which older men scared away with shell rattles.
After harvesting, the kūmara tubers were put into rua kūmara. These were underground pits with rectangular roofs, cleaned with fire, and sealed with small wooden doors to keep out pests. These pits became common after 1500 AD. Control over rua kūmara was a sign of importance in Māori society. Rua kūmara were built on slopes for good drainage. Kūmara were placed on shelves inside the pits and regularly checked for rot. The pits were usually reused.
Traditional ways of eating kūmara included sun-drying smaller tubers (kao), grating them (roroi kūmara), cooking them in a hāngi (earth oven), roasting them, or boiling them. Kōtero is fermented kūmara, often from tubers that started to rot. It looks shriveled but stays sweet.
Since 2010, kūmara has been grown using traditional methods at a garden called Te Parapara in the Hamilton Gardens.
Social and Religious Importance
The origins of kūmara are also explained through Māori stories. Rongo-māui, a star, stole kūmara from the heavens. His wife, Pani-tinaku, gave birth to the earthly forms of kūmara. She was asked to cook the kūmara to remove its sacredness. Another story tells how kiore (rats) became kūmara thieves. And how hawk-moth caterpillars attack kūmara as revenge for Rongo-māui's theft.
Kūmara became linked to Rongo-mā-Tāne, the god of farming and peace. Small statues and carved pegs representing Rongo were placed near kūmara fields. Because kūmara was so important, planting involved special rituals. The yearly planting and harvest were like acting out the story of Rongo-māui. On the first planting day, a priest would say a prayer to Rongo-mā-Tāne. Then men would use digging sticks to prepare the fields, followed by women and children. After planting, the fields were made sacred, so only weeders and pest removers could enter. During harvest, the first kūmara were offered to the gods in a ceremony. After the harvest, big feasts were held.
Areas best for growing kūmara (light, sandy soils, frost-free, north-facing) were often fought over by different Māori tribes. In the Classic period of Māori history, when farming became more common, areas where kūmara grew well often had more fortified villages and larger populations.
Modern Cultivation
Kūmara became less important when potatoes were introduced by Western sailors in the 1780s. Potatoes could grow in colder places and didn't need sacred rituals, so women or slaves could grow them. Old kūmara types continued to be grown, but by the 1800s, they were mostly replaced by American types brought on whaling ships. Around 1819, an American whaler brought a North American type that was larger. This became known as merikana (American). The waina (vine) type was brought in the 1850s from Rarotonga. This type was grown from vine cuttings, not roots, which is how it got its name.
The types of kūmara grown today for sale mostly come from those brought on whaling ships. In the 1940s and 1950s, a disease called black rot started to affect kūmara crops in the North Island. Chinese New Zealand gardeners Fay and Joe Gock developed a disease-resistant type of kūmara in the 1950s. This new type, called Owairaka Red, was released in 1954. The Gocks gave this new type to farms in New Zealand's main kūmara growing areas, saving the crop from black rot.
In the 21st century, most kūmara for sale is grown in Northland. In 2020, about 1600 hectares of land grew 24,000 tonnes of kūmara each year. The three main types are Owairaka Red, Toka Toka Gold, and Beauregard (orange). Owairaka Red is the most common. Toka Toka Gold was introduced in the 1960s and became available in 1972. It's named after a peak near Dargaville. Beauregard, developed in the US in 1987, came to New Zealand in 1991. Two new types, Purple Dawn (purple skin and flesh) and Orange Sunset (purple skin with orange and purple flesh), were released in 2014.
