University of Florida Researchers Grow Plants in Moon Soil

NASA plans to return to the moon sometime this decade, with the goal of setting up a permanent base on the lunar surface. But shipping supplies to the moon will be extremely expensive, leading scientists to search for alternative methods to feed earth’s first space colonists.

Geologists from the University of Florida have managed to grow plants in soil gathered from the lunar surface.

The plant chosen is one you have undoubtedly seen, but may not have heard of: Thale Cress (Arabidopsis thaliana) a weed that often grows alongside roads, in cracks along walls, and even in parking garages. It was chosen because of its hardiness and because its genome has been fully sequenced and is well understood.

It’s not likely a plant on the top of anyone’s dinner menu, though parts of it are edible, it is related to plants not unfamiliar to dinner tables on earth. Thale Cress is the genetic cousin of cabbages, broccoli, and rapeseed.

The “soil” gathered from the moon is not actually soil at all but regolith, a rocky substance devoid of organic material that sits on top of bedrock. It may not technically be soil, but it is the closest thing we have on the moon.

Geologists at the University of Florida have been wanting to study the efficiency of lunar soil for growing plants for a while, but the soil is in short supply. Only 842 lbs (382 kg) of soil and rocks were brought back by the Apollo missions, which may sound like a lot, but it is all we have until we go back for more.

Because of this, the research team was denied by NASA twice in their requests to obtain some of the lunar regolith, but the third time ended up being a charm. NASA sent the team 12 grams of soil from three different Apollo missions: 11, 12 and 17.

This is likely because NASA’s Project Artemis is set to return astronauts to the moon sometime this decade, with the eventual goal to build a permanent settlement on the lunar surface.

The results of the study, published Wednesday in Communications Biology, were promising. Researchers created four cultures for each of the three sites and a control group made out of volcanic ash from the earth, each culture received one gram of soil from their respective site.

Within 48 to 60 hours, every plant began to germinate and grow, though to varying degrees of success. Unsurprisingly, the control group fared the best. The worst was Apollo 11’s sample, which came from its landing site, the Sea of Tranquility. The second was Apollo 12’s Ocean of the Storms and the best performing lunar sample was Apollo 17’s, gathered from Taurus-Littrow.

This is likely because of the geological age of each site. The Sea of Tranquility is the oldest and therefore has been exposed to the Sun’s radiated rays for the longest amount of time. Taurus-Littrow is the youngest, having been exposed to the surface relatively recently through a series of meteorite impacts.

The plants in all three lunar samples struggled. There are over 1000 genes out of the 30,000 genomes in Thale Cress that can be activated to help the plant grow in difficult conditions. Each sample activated hundreds of them. The Apollo 11 sample activated 465, the Apollo 12 sample activated 235, and the Apollo 17 sample activated 113 of the stress genomes. The plants also had visible signs of ill-health, including red and black marks on the leaves.

Still, they managed to grow, which is very encouraging. Geologist and study co-author Stephen Elardo explained what future lunar colonists would be able to do to help the plants thrive in a permanent settlement. “What we could simply do in the absence of other constraining factors, is land and establish a habitat on a lunar surface that is significantly younger than the Apollo 11, 12, and 17 sites.”

This is not the first time scientists have studied Thale Cress in relation to space. It was used by NASA to study plant growth in zero gravity on the International Space Station. Those plants had the benefit of specialized growth units, rather than radiated regolith, but they apparently adapted quite well.