Growing Underground is a hydroponic vertical farm—using 70% less water than your typical farming operation. They utilize a closed-loop ebb and flow system where water with nutrients floods the beds of sprouts a few times a day and then is recycled through a reservoir and reused. The plants float in a substrate made from recycled wool carpeting. Lights sit above the plants and are turned on and off to simulate daylight and night time. In the UK, power costs less at night, so the lights are off during the day and turned on in the evenings. In addition to the water and lights, the grow room also has a system of fans to keep air circulated. Given their unique insulated location,108 feet underground, the tunnels naturally provide a consistent microclimate year round. The whole grow process takes between 10-20 days from seeding to harvest, based on the plant's specific growth cycle.
Growing Underground has been supplying food to the market since 2016, and they currently grow over 16 varieties of microgreens ranging from more common sprouts like sunflower to more exotic varieties like wasabi and mustard. While the proof of concept was with lettuce, the co-founders decided to pivot to growing microgreens because they take less time to grow and are a desirable commodity for local chefs and home chefs too. They sell directly to Whole Foods, M&S, and a handful of other London-based grocers and restaurants. The just-picked greens are marketed, for some stores, as a 'micro-salad' offering a delicious (I can attest) spin on your typical salad. Although small, these plants pack your mouth with a surprising, flavorful bundle of taste (and high nutrient content too.)