Jan 25 (Reuters) – Retail giant Walmart Inc said on Tuesday it is investing in indoor vertical farm Plenty as part of a $400 million funding round and will be buying leafy greens from them for its stores in California.

The investment in the South San Francisco startup that grows leafy greens under banks of lights is one of the biggest in the indoor farming business, and the distribution deal from Walmart is a sign of mass market appeal from an industry that has not delivered on early expectations. High costs have been a challenge for the industry.

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