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In Đà Lạt, Greenhouses Revolutionize Farming, but at What Environmental Cost?

Plastic greenhouses in the city of Đà Lạt may protect farmers from the impacts of erratic weather, but the environmental toll of agri-plastics is building in the agriculture-dependent region.

Cam Ly landfill was, until it was shut down in 2020, the primary dumping ground for the city of Đà Lạt. Five kilometres from central Đà Lạt in the Central Highlands region, the landfill was the final destination for the majority of plastic used in agriculture in the hilltop locale. But in August 2019, heavy rain prompted an outpouring of trash, sending plastic sheeting from greenhouses and untreated agrichemical bags and bottles rushing downhill. The incident covered lowland farms in thousands of tons of waste.

Greenhouses cover approximately 2,425 hectares within Đà Lạt’s city limits — equivalent to more than 4,500 football pitches. Photo by Thịnh Doãn.

Đà Lạt is the capital of Lâm Đồng Province. The municipality is known for its temperate climate, rolling hills, pine trees and agriculture. Over the past two decades, plastic greenhouses have enveloped much of the landscape within the city and surrounding areas. They have increased agricultural production and raised farmers’ income. However, greenhouses are also contributing to rising temperatures, floods, pollution of waterways and the build-up of agri-plastic waste, with no formal system for recycling.

In the city’s Ward 12, greenhouses cover 83.7% of farmland. In wards 5, 7 and 8, they occupy more than 60%. Photo by Thịnh Doãn.

Discarded agricultural plastics in Đà Lạt’s Ward 5, where greenhouses  cover more than 60% of agricultural land. Photo by Thịnh Doãn.

Plastic shield against a volatile climate

While greenhouses are expensive, they are a “mark of achievement” for many farmers, often lead to higher yields, and act as a “safety net against climate change,” says Nguyễn Châu Bảo, co-founder of Act Now, a Đà Lạt-based environmental non-profit. With increasingly unpredictable weather patterns in the region, greenhouses allow farmers to control the environment and shield crops from harsh conditions.

Plastic sheeting allows non-native plants, like tomatoes, to be grown all year, protected from heavy rains, humidity, hail and frosts. Heavy downpours can cause roots to become waterlogged, split tomatoes’ skin, and lead to bacterial infections in the plant. For this reason, the majority of tomatoes are grown inside greenhouses in Đà Lạt.

After dark, bulbs light up greenhouses in Đà Lạt to prompt overnight growth. Photo by Govi Snell.

Hiền, a farmer in Đà Lạt, says he relies on plastic sheeting to ensure a stable growing environment for his crop of flowers. He rents the land where he has a small greenhouse for six-month periods, so it is vital his crops come to harvest reliably within this time. From Hiền's roadside flower farm, greenhouses can be seen in every direction.

Hiền says that without a greenhouse rain would damage the buds of the flowers he grows. Once these flowers have bloomed, they will be packaged in plastic and sold to Hanoi and South Korea. Photo by Thịnh Doãn.

Workers cut and package flowers for sale inside a large greenhouse in Đà Lạt. Photo by Thịnh Doãn.

Ecological toll of plastic greenhouses

Despite the benefits for farmers, greenhouses have a heavy ecological impact on the region. Võ Xuân Hạo Khuyên, who was born in Đà Lạt in 1995, used to be able to see wide swaths of pines from her home. The green space has since disappeared.

“Right now it is just the white colour because all you see is the greenhouses,” she explains. The problems caused by rapid greenhouse development are easy to see, Khuyên adds, listing temperature increases, light pollution and floods.

Temperatures in Đà Lạt increased by between 1 and 1.5°C between 2008 and 2018, and the rise is expected to continue, according to statements from Vũ Ngọc Long, former director of the Ho Chi Minh City-based Southern Institute of Ecology, in a local news report. While urban development has played a role in the temperature rise, Long said that the immediate area surrounding a greenhouse is 3 to 5°C hotter than areas in similar climates without plastic-covered structures.

The area immediately surrounding greenhouses can be several degrees warmer than areas in similar climates without plastic-covered structures. Photo by Thịnh Doãn.

Plastic greenhouses prevent rain from being evenly absorbed into the earth. Photo by Thịnh Doãn.

While rising temperatures are a concern, floods have already had a severe impact on the region and are now a regular occurrence during the rainy season from May to October.

When raindrops hit the greenhouse, they cannot be absorbed by the soil below. Instead, says Khuyên (who has studied the sustainability problems created by greenhouses), the runoff from the tightly packed greenhouses creates streams that combine after heavy rain, flooding the city’s drainage system.

“We are a mountain city. We aren’t supposed to have floods, but at the end of the day we have floods, very heavy floods that even killed people,” Khuyên says.

Experts cited concrete paving, deforestation and the glut of greenhouses as primary causes of Lâm Đồng’s floods in a 2019 report on environmental disasters in Vietnam. Photo by Thịnh Doãn.

In August 2019, the damage from the severe floods that hit Đà Lạt and surrounding areas extended beyond swamping the land with trash from the landfill. More than 12,000 homes were flooded, 10,000 hectares of crops were damaged and 11 people died. In 2020, 44 people were forced to evacuate a Đà Lạt hotel when the structure became at risk of collapsing during a downpour. That same year, a runner died after being washed away by a flash flood during the Đà Lạt Ultra Trail marathon.  

Districts downstream of Đà Lạt along the Cam Ly River which flows through the city are also impacted by the greenhouse-amplified flooding. During last year’s rainy season, areas of Đà Lạt and Đức Trọng District, approximately an hour’s drive from the capital city, flooded within 12 hours of heavy rain as the water level rose. Farmland was inundated, households were forced to relocate and sections of a national highway were submerged.

“Floods never used to appear in Đà Lạt,” says Phạm Trọng Phú, who grew up in Lâm Đồng Province and now works for SNV Netherlands Development Organisation, a non-profit with a base in Đà Lạt. “Many disasters have followed with the development of greenhouses.”

An alternative way to farm?

LVDM Organic Pilot Farm is experimenting with growing beefsteak tomatoes outdoors, but this year the crop failed after heavy rain hit the area in mid-March. “The rain came two months early… That’s climate change,” says Leonie Ha, the farm’s project manager. Photo by Thịnh Doãn.

Les Vergers du Mekong (LVDM) Pilot Organic Farm is located down a steep, dirt road in Đà Lạt’s Ward 3. With funding from LVDM as well as the GIZ (German development agency), the team of six running the farm can try eco-friendly methods without direct impacts on their livelihoods. Fruit is grown to be juiced and bottled for sale, and the only plastic sheeting to be found is a small covering that protects seedlings.

Although many farmers in the region have taken up greenhouse farming because of its stable yields, others believe the environmental toll of the plastic coverings outweighs the benefits.

Staff at LVDM are leaving the tomatoes to fully ripen before gathering the organic, fungus-resistant seeds for reuse. “We are allowed to fail,” Ha says. “[Most] farmers cannot do this kind of thing.” Photo by Thịnh Doãn.

Trần Thị Mỹ Phượng, a farmer who works at LVDM, waters beetroot seedlings. “The number of people doing [eco] farming like this is increasing slightly but the reality is that greenhouses [are growing] significantly faster,” she says. Photo by Thịnh Doãn.

Nguyễn Nhi is the farm manager at Rừng Thông Mơ Farm & Bistro, a winding 25-minute drive from central Đà Lạt through pines with sections occupied by greenhouses. During the dry season from November to April, Nhi says, heat is trapped inside the greenhouses, causing temperatures in surrounding areas to increase. Additionally, the moist atmosphere inside greenhouses is conducive for worms, which eat the vegetables, causing farmers to rely heavily on pesticides.

At Rừng Thông Mơ, food scraps are composted in these large plastic barrels for three months to be used as fertiliser. “I am pro natural farming because it’s not just good for the plants, it’s not just good for nature, but also for the people, for the farmer’s health,” says farm manager Nguyễn Nhi (right). Photo by Thịnh Doãn.

Lettuce is grown without plastic at Rừng Thông Mơ. Photo by Thịnh Doãn.

Rừng Thông Mơ has no plastic greenhouses. Instead, herbs and green leafy vegetables are grown using intercropping methods, and rice husks are burnt to deter pests. The farm produces little to no plastic waste, avoiding the harmful impact agri-plastics can have on soil health.

“Of course I want people to use fewer greenhouses but it’s hard because it comes with efficiency. You can make more money,” Nhi says. “It is hard to ask them to go back to the natural way of farming. I expect the number of greenhouses to double.”

Nguyễn Duy, co-owner of Rừng Thông Mơ, picks herbs at the farm. Photo by Thịnh Doãn.

Plastic waste is not recycled

Over time, due to use and UV exposure, plastic degrades and needs to be replaced. The majority of the plastic sheeting used for greenhouses in Đà Lạt is burnt or buried once it is no longer usable.

Nguyễn Hồng Quân, who grew up in Đà Lạt and is now director at the Institute for Circular Economy Development, a research unit within Vietnam National University in Ho Chi Minh City, says that currently no “holistic or systematic solution” is available to recycle agri-plastics in Lâm Đồng Province. The majority of agri-plastics end up in landfills.

“I think this is quite a big issue now. We see a lot of plastic waste from greenhouses,” Quân says, adding that the difficulty of managing plastic sheeting is compounded by farmers being dependent on greenhouses for their livelihoods.

Plastic sheeting used in agriculture gradually degrades and has to be replaced. Photo by Govi Snell.

Vietnam has no formal system for recycling plastic materials, despite a new environmental protection law that took effect in January. The mandate — which comes without funding — makes the country’s local governments responsible for sorting and recycling waste.

Miquel Angel sits on Vietnam’s Tourism Advisory Board and surveyed some landfills this April. He has not seen improvements in waste management and says trash is still being buried, burned or allowed to leak into the country’s waterways.

“This is a lot of talk,” he says of the new regulation. “Nobody is taking any action.”

Styrofoam seedling trays pile up at the side of the road in Đà Lạt. Most agri-plastics used in the region are not recycled. Photo by Govi Snell.

Plastic disintegrates next to a greenhouse in Đà Lạt. Photo by Govi Snell.

“Greenhouses are like single-use plastic, they should be banned,” says Paul Olivier, who has lived in Đà Lạt for 16 years and supports farmers with transforming waste into feed, fuel and fertiliser. Olivier explains that he sees plastic sheeting, styrofoam, and bottles and bags for chemical pesticides and fertilisers in Lâm Đồng’s streams, lakes and rivers, where fish often float lifeless at the surface.

Lan, the owner of a vựa phế liệu in Đà Lạt, says she rarely buys plastic sheeting and has no set price for greenhouse covers. Photo by Thịnh Doãn.

Informal waste collectors are the driving force behind the management of Vietnam’s plastic waste, approximately 27% of which is recycled. Waste pickers gather plastic bottles, cardboard and a variety of other discarded materials to sell at a local vựa phế liệu — a scrap collection centre where recyclables can be bought and sold.

At another informal recycling hub near a high density of greenhouses, used plastic sheets sell for a meagre VND10,000 (US$0.43) per kilogram. Photo by Govi Snell.

Action for change

Although not yet approved, Lâm Đồng Province’s Department of Agriculture and Rural Development has put forward a scheme for the management of greenhouse farming with specific goals set for 2025 and a vision for 2030. The document acknowledges that the province currently has no regulations on the management and construction of greenhouses, and that local authorities do not have effective solutions to lessen the environmental impacts of greenhouses.

Nguyễn Thanh Thảo Nhi (left) and Nguyễn Châu Bảo (right) are co-founders of Act Now, an environmental non-profit in Dalat. “Agriculture is one of the biggest factors that contributes to environmental degradation here,” says Bảo. “Greenhouses create a lot of problems.” Photo by Thịnh Doãn.

The government wishes to control the proportion of greenhouse area in agricultural land to below 40% in all of Đà Lạt’s 12 wards. All greenhouses illegally built on forest land, ecologically sensitive areas, and historic, scenic and culturally significant land will be cleared away by 2025. By 2030, the government also wants to upgrade substandard greenhouses, manage greenhouse construction, and build new modern greenhouses in the province.

At trash cleanups, members of Act Now chant, “Đà Lạt is our home, not a landfill.” Photo courtesy of Act Now.

“I really want to look at the positive side,” says Bảo of Act Now. “It has to be a community change, a very big systemic change if you want to see a reduction in plastic waste or agricultural waste. I think it is the biggest problem we need to solve.”

This article was originally published on The Third Pole under the Creative Commons BY NC ND licence.