Quang Ngai is a major chrysanthemum-growing centre in central Vietnam, supplying 500,000-600,000 potted plants to the market each Tet. Most are grown in Ve Giang Commune, where flower fields glow under electric lights after dark.
Every evening at 6 pm, hundreds of 12-watt fluorescent bulbs automatically switch on across Nguyen Thanh Tien's field of more than 1,000 chrysanthemum pots. Similar lighting systems operate across hundreds of neighbouring farms.
Tien said the lights remain on until 3-4 am, with bulbs suspended above the plants at three-metre intervals.
The artificial lighting delays bud formation, allowing the chrysanthemums to grow taller and more uniformly before flowering.
"Without lighting, the plants start budding at just 40-50 cm and bloom unevenly. With lighting, they grow to 70-80 cm, producing larger, more colourful flowers," he said.
Seedlings are initially grown for about 15 days to establish their roots before undergoing three months of overnight lighting.
Farmers then switch off the lights, usually in late November or early December of the lunar calendar, to encourage simultaneous bud formation.
Once buds appear, smaller ones are removed so the plants can produce fewer but larger flowers.
Another grower, Nguyen Van Hoang, cultivates 800 pots across 900 square metres for the Tet market.
He estimates that 500 square metres can accommodate 400 pots, with electricity for overnight lighting costing about VND 2 million (USD 76) per growing season.
"The additional cost is considerable, but the flowers look better and fetch higher prices. That's why every chrysanthemum grower in Ve Giang uses overnight lighting," Hoang said.
Chrysanthemum pots range from 50 cm to one metre in diameter and typically sell to traders for VND 150,000-300,000 each during Tet.
Growers in Ve Giang can earn VND 40-60 million per season, although production costs account for 60-65 per cent of the selling price.
"The work is demanding because the flowers need nearly four months of care. If the weather is favourable and pests are limited, growers can earn a decent income," Hoang said.
Doan Viet Van, chairman of the Ve Giang Commune People's Committee, said favourable weather had supported flower growth this year.
Local authorities have also invested in electricity infrastructure to help farmers illuminate and maintain their crops.
Besides serving customers in Quang Ngai, chrysanthemums from Ve Giang are sold by traders in Danang and Gia Lai Province.