TAIPEI, Taiwan — Chang Chen-kai is part of Taiwan's new generation of high-tech farmers that is harnessing the island's technological edge in light-emitting diodes to grow vegetables indoors under bright LED lights.

Chang works in an air-conditioned "grow-room" at a plant factory operated by ARWIN, a biotechnology company, where plants grow in nutrient-filled water instead of soil and the temperature and humidity are controlled. LED lights imitate the cycle of night and day.

These high-tech indoor farms yield more crops per area than soil, and don't need traditional toxic pesticides. Plants grown under LED lights grow twice as fast because the intensity of lights and nutrients provided in the water, growers say.

"To grow vegetables in the water (under lights), you need less land," Chang said, and "you don't need pesticides."

Such plant factories are gaining popularity for raising everything from common lettuce to the exotic ice plant, a thick leafy vegetable from South Africa that looks like it has water bubbles on its leaves and can fetch $400 per kilogram.

In recent years, Taiwanese manufacturers have been able to produce cheaper LED lights that consume less electricity and give off light that mimics the intensity and spectrum of sunlight.

TingMao Agricultural Biotechnology was an early pioneer, starting its plant factory in 2007, and today is the leading producer of LED-grown vegetables in Taiwan. It has also set up its own restaurant using vegetables from its factory to allow consumers to taste the vegetables themselves.

But Lily Chang, a food writer and professor at Innovative Institute of Technology, isn't convinced that LED-grown vegetables are as nutritious as those grown in soil.

"Natural soil-based plants get nutrients from soil," she said, that are "extremely difficult for us humans to manufacture."

Consumers should insist that the government to draw up regulations on the chemicals used in the water of LED-grown plants and hygienic standards, she said.