NASA germinated corn seeds during spaceflight; seedlings showed altered root growth and twisted shoot patterns in microgravity

Somewhere above our heads around the Earth’s orbit, a bunch of corn seeds managed to do what most plant owners had feared their plants might succeed in doing: they sprouted. The mission's growth record lists germination as effectively complete across the batch, though the precise percentage reported in NASA's own data has not been independently verified beyond that record. However, since there was no soil, no light, and definitely no gravity, the plants got thoroughly disoriented. Due to the lack of any sense of direction, the roots started going sideways while the shoots curled up into loops instead of growing vertically.

According to the Open Science Data Repository maintained by NASA as a database for all the spaceflight biology experiments conducted by the agency, such behavior has been observed in other plants cultivated aboard the International Space Station before. The problem of plants being unable to determine the direction they need to grow is a bigger deal than just having some twisted corn sprouts.

NASA and private-company plans for Mars agriculture assume astronauts will be able to partially grow their own food en route to and on the red planet, and that assumption depends in turn on plants reliably knowing which way is "up." Experiments like this one are a reminder that they don't always, a limitation space biologists have actually been documenting since some of the earliest plant experiments flown in the 1960s and 1970s, not a discovery.


Why plants usually know which way is down

Plants on Earth possess an internal compass. Root tips contain specialized gravity-sensing cells called statocytes, which hold amyloplasts, small, starch-filled organelles that settle downward under gravity's pull and signal to the cell which way is "down.” Based on that signal, roots grow, and plants grow the shoots away from that direction. This mechanism has been working for hundreds of millions of years. Remove gravity, and the compass stops pointing in the right direction.

The part nobody warned you about

Corn, in particular, stands out as an interesting example because it was established many years ago that the roots of maize in the absence of light may not grow downwards on Earth, either. Plant physiology studies carried out in the past concerning maize revealed that certain kinds of corn require light exposure to grow in the right direction, and without it, their roots could grow sideways, a condition referred to as diagravitropism.

On Earth, gravity is still present and doing most of the work in that scenario; darkness just seems to interfere with how well the plant reads that gravity signal. In microgravity, the gravity signal itself is largely gone, so the mechanism isn't identical, but it raises the related possibility that light may serve as a secondary directional cue plants can fall back on when gravity is weak or absent, meaning growing in total darkness in orbit could remove a second potential source of orientation, not just the first.

This idea is corroborated by modern space biology research. A 2024 study titled “Light has a principal role in the Arabidopsis transcriptomic response to the spaceflight environment,” by Zhou et al., published in the journal NPJ Microgravity, compared Arabidopsis thaliana, not corn, grown in light versus darkness aboard the ISS. It found that light-grown leaves showed roughly ten times as many spaceflight-related changes in gene expression as dark-grown leaves, and that light and dark conditions triggered different, sometimes opposite, patterns of gene activity. In other words, in this particular model plant, light did more than fuel photosynthesis; it shaped how strongly and in what direction the plant's genes responded to the stress of spaceflight. Whether the same holds in corn, a much more distantly related crop, hasn't been directly tested.

The twisted roots are not random either

The side and helical root patterns found in the plants grown under space conditions have a scientific term: “root skewing.” A 2020 Frontiers in Plant Science paper titled “Root Skewing-Associated Genes Impact the Spaceflight Response of Arabidopsis thaliana,” by Califar et al., found that root skewing also occurs in microgravity, suggesting genes involved in root structure and cell-wall formation may play a role.

That's a meaningful finding because root skewing had previously been treated as purely a gravity-related artifact; seeing it in microgravity too suggests genetics, not just the absence of gravity, shapes how a root grows crooked. Here again, the underlying research is in Arabidopsis, a small dicot model plant, rather than corn, a monocot, a useful clue about mechanism, but not a direct finding about maize itself.

The uncomfortable part of the Mars food conversation

It is hard not to be impressed by images of pristine Martian greenhouses in every pitch deck for the next big space venture. But as seen from the actual output of NASA's data archives, the truth is a bit different. Germination in orbit is not an issue, and that's not even in debate. The issue that needs to be settled here is the ability of the seedlings to develop into something remotely resembling an actual crop, which involves a lot more in terms of light and orientation engineering than what our technology currently allows.

In an era where colonizing Mars in a decade sounds perfectly feasible because of Silicon Valley marketing, this experiment is a useful reality check. Dinner in space will be a bit more complicated. This is not to say that space agriculture is doomed. But it certainly means that the easy questions, such as whether seeds will germinate or not, have already been answered long ago.