The researchers had no idea if anything would sprout in the moon’s harsh soil and wanted to see if it could be used to grow food by the next generation of lunar explorers. The results stunned them.
“Holy cow. Plants actually grow in moon stuff. Are you kidding me?” said Robert Ferl of the University of Florida’s Institute of Food and Agricultural Sciences.
Ferl and his colleagues planted watercress from Thale in the lunar soil rendered by Apollo 11’s Neil Armstrong and Buzz Aldrin, and other moonwalkers. The good news: all the seeds have germinated.
The downside was that after the first week, the coarseness and other properties of the lunar soil stressed the small flowering weeds so much that they grew more slowly than seedlings planted in fake Earth lunar soil. Most moon plants ended up being stunted.
The results were published Thursday in Communications Biology.
The longer the soil was exposed to cosmic radiation and solar wind on the moon, the more plants seemed to degrade. The samples from Apollo 11 – exposed a few billion more years to the elements due to the older surface of the Sea of Tranquility – were the least conducive to growth, the scientists said.
“It’s a big step forward to know that you can grow plants,” said Simon Gilroy, a space plant biologist at the University of Wisconsin-Madison, who had no role in the study.
“The real next step is to go do it on the surface of the moon.”
Lunar dirt is full of tiny shards of glass from micrometeor impacts that have spread all over the Apollo lunar landers and worn down the space suits of moon walkers.
One solution could be to use younger geologic spots on the moon, such as lava flows, to dig up planting soil. The environment could also be changed, by altering the nutrient mix or adjusting artificial lighting.
Only 382 kilograms of moon rock and soil were brought back by six Apollo crews. Some of the earliest moon dust was sprinkled on plants quarantined with Apollo astronauts in Houston after returning from the moon.
Most of the lunar reserve remained locked away, forcing researchers to experiment with simulated soil made from volcanic ash on Earth. NASA finally distributed 12 grams to researchers at the University of Florida early last year, and the long-awaited planting took place last May in a lab.
NASA has said the time has finally come for such an experiment, with the space agency looking to put astronauts back on the moon in a few years.
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The ideal situation would be for future astronauts to tap into the endless supply of local soil available for indoor planting rather than setting up a hydroponic or all-water system, the scientists said.
“The fact that something has grown means that we have a very good starting point, and now the question is how to optimize and improve,” said NASA space biology program scientist Sharmila Bhattacharya.
Florida scientists hope to recycle their lunar soil later this year, planting more thalus cress before eventually moving on to other vegetation.