A harried commuter rushes through a Tokyo station hoping to catch the next train home.

But first, a quick stop at a store to pick up a fresh head of lettuce. So fresh, in fact, that it is grown right there at the train station, cultivated using technology to ensure that it is raised under the most optimal conditions.

Tokyo-area rail operator JR East will soon make this possible -- and its stations greener while also cashing in on the indoor farming boom.

The company, officially known as East Japan Railway, borrowed the idea to grow vegetables indoors from German startup Infarm, which counts the rail operator as an investor. Infarm has partnered with the Japanese grocery chain Summit to grow produce using grow lights and sell it on-site.

Since January, a Summit Store in Tokyo's Adachi ward has grown lettuce and other vegetables in giant cases inside the location. At 213 yen ($1.94) per head of lettuce, its almost double the price of lettuce grown outdoors. The store plays up freshness as the selling point.

Infarm has also built indoor farms within stores run by Kinokuniya, JR East's upmarket supermarket subsidiary. A total of five Summit and Kinokuniya stores in the Tokyo area currently host these farms.

Now JR East is looking at expanding the operation to shopping complexes inside train stations. The equipment Infarm provides can be installed in a decentralized manner so that massive greenhouses do not occupy the spaces.

Indoor farming has grown in popularity as a way to limit the ecological impact of conventional farms, which account for 70% of the water used around the world. Global warming and desertification will diminish the area of arable land.

Shifting farms indoors is seen as a way to sustain the agricultural industry. Thanks to automatic controls, the facilities are able to curb the amount of water consumed. Vertical farming, in which crops are grown on walls, in urbanized places like Singapore that have limited farmland will be able to secure large amounts of space to grow food.

Infarm consumes 95% less water than that of an outdoor farm, the company says. Just 2 sq. meters of space can produce yield equivalent to a 250-sq. meters of farmland.