Sensei Farms Lanai’s greenhouses mix old and new technology

LANAI CITY >> Paving over red dirt that was once part of the most productive pineapple plantation in the world might not seem like the way to start a positive transformation of agriculture on Lanai.

But inside the first two of nine enormous concrete- floor greenhouses on the former Pineapple Isle, a bounty of produce is being built up in what operator Sensei Farms Lanai describes as a partially controlled environment driven by a mix of old and new technology, from radiators to computers.

The primary attribute of a hydroponic farm is a supply of nutrient-infused water that feeds plants suspended in trays.

At Sensei Farms, on 5 acres of former pineapple fields near the Lanai airport, computers control watering and nutrient distribution programmed for specific plants that are arranged in rows on trays that rest on stands or are suspended on wires.

>> READ MORE: Lanai undergoes agricultural transformation using hydroponic greenhouses

The greenhouses also were built with less sophisticated but effective regulators of air temperature, light and harmful elements.

The sides of the structures are made of clear, rigid polycarbonate plastic. The roofing material is two layers of polyethylene, which allows some ultraviolet rays through. To further control UV rays, a mesh ceiling blocks some sunlight or can be retracted to allow more.

The entire greenhouse is designed to withstand winds up to 105 mph.

To regulate air flow and temperature inside, the leeward side of the buildings has two rows of exhaust fans. The bottom row pulls air out from the lower regions of the greenhouse space, while an upper row functions like an attic fan, pulling out more of the hotter air that rises.

Ceiling fans help distribute air around the plants.

Sensei also has different air control features depending on whether the greenhouse is designed to grow plants that prefer a cooler or warmer environment.

For cooler-living plants including lettuces, a giant radiator grill stretches across the windward wall. Water drips through the grill, and tradewinds blow cooler air into the greenhouse.

In the warmer greenhouse for plants including tomatoes and cucumbers, there is no wall radiator. Instead, elevated water pipes snake between rows of plant trays. Hot water is run through the pipes at night, and heat radiating off the pipes is circulated among the plants using “tube fans” (essentially long bags with holes along their sides out through which air is blown) to counteract cooler outside nighttime air.

Sanitation is also something Sensei aims to control. Anyone handling the plants typically puts on sterile blue gloves.

“We try to keep it as pristine and as untouched as possible,” said Molly Stanek, senior vice president of the farm operation.

Also, the entrance to each greenhouse features two sets of doors that help keep out pests and are separated by a small lobby space with a disinfectant bath for footwear.

Two years ago Sensei Farms co-founder Larry Ellison, who bought 98% of Lanai in 2012, estimated it would cost $15 million to develop a farm capable of producing close to 1.5 million pounds of produce annually.

Stanek declined to share an updated cost for the project, which in addition to the greenhouses includes a packing and cold-storage building and a “farm house” outfitted with a science lab, computer room, classrooms, employee locker room and an event space with teak interior finishes and landscaped yard with a distant ocean view.

En Young, Sensei Farms general manager, said the strategy and investment have grown since Ellison shared his conceptual vision and cost for the project.