Indoor farm: how it could work on the Moon and Mars

Indoor farm

Topic: hydroponics

Rows of plants grown under lights in water instead of soil, producing fresh food year-round in a small space.

Purpose

Fresh food in space

First space salad

Lettuce eaten on the ISS, 2015

Grown in

Water and nutrients, under LEDs

Also used on Earth

Vertical farms in cities

Possible future How it would work

An indoor farm would grow leafy greens, herbs, tomatoes, peppers and more in stacked trays, watered with nutrient solution and lit by LEDs tuned to the colors plants use best. Computers would control temperature, humidity and light. Fresh food would add vitamins and variety to packaged meals.

Lettuce growing under LEDs in NASA's Veggie system on the International Space Station. Photo: NASA, Public domain, via Wikimedia Commons

Real world Plants in space today

NASA's Veggie system on the International Space Station grows plants under red, blue and green LEDs. In 2015, astronauts ate red romaine lettuce grown on the station, the first time NASA astronauts ate food grown in space. Since then crews have grown cabbage, mustard greens, chilli peppers and flowers.

Growing plants in weightlessness has surprises: water does not drain downward, so roots can drown or dry out, and plants rely on light rather than gravity to know which way to grow.

Real world Indoor farms on Earth

"Vertical farms" in cities grow crops indoors in stacked layers, using much less water than fields because water is recycled. They are good for leafy greens but use a lot of electricity for lights, so engineers are working to make them more efficient.