NASA sent seeds into space for nearly 6 years; after they returned, 132,000 experiment kits reached 3.3 million students in 30 countries

By the end of March 1990, about 132,000 experiment kits had gone out to 64,000 teachers in roughly 40,000 classrooms. They reached 3.3 million students, from kindergarten through university, in every U.S. state and 30 foreign countries. Each kit held tomato seeds from two sources: some that had circled Earth on a NASA satellite for almost six years, and some that had spent the same stretch in a climate-controlled warehouse. Students planted both, measured what came up, and mailed their results to NASA as part of SEEDS, short for Space Exposed Experiment Developed for Students.

NASA started the project out of concern that fewer young people were choosing careers in science and engineering. It believed that attitudes toward those subjects form well before secondary school. The agency wanted a project big enough to involve a great many students and hands-on enough to let them work with material that had actually flown in space. The outcome was also genuinely open, since the seeds might have died, mutated or come home untouched.

A one-year plan that ran long

NASA flew 12.5 million Rutgers tomato seeds in five aluminum canisters on the Long Duration Exposure Facility, known as LDEF. Space Shuttle Challenger placed the satellite in orbit in April 1984, and the seeds were meant to stay up for about a year. Inside each canister, four layers of seeds sat in Dacron bags, sealed at normal air pressure and 20 percent humidity, with radiation dosimeters between the layers. Park Seed, the South Carolina company that supplied them, chose the Rutgers California Supreme variety for its uniformity and reliable germination. The company had already tested how launch and re-entry forces affect seeds in a small experiment aboard a 1983 shuttle flight.


Delays in the shuttle program and the loss of Challenger in 1986 pushed retrieval back indefinitely, and LDEF spent 69 months in orbit. Columbia's crew recovered it in January 1990, and the seed tray was the first experiment taken off the satellite. The same tray also carried two million seeds of 120 varieties in one sealed canister and two small vented ones. Seeds in the sealed canister survived at a better rate than seeds kept in Park Seed's storage facility. Some seeds in the vented canisters also came through direct exposure to vacuum.

Inside the kits, and what came back

The kit for grades 5 through 9 held an instruction manual, an activity book and a data booklet. It also contained a letter from the U.S. Department of Agriculture about the safety of experimenting with the seeds. The seeds came in two packets of 50, one from space and one from Earth. Teachers of younger children asked for that version so often that it ended up in many classrooms from kindergarten to fourth grade. Of the data returned, 77 percent came from grades K through 9, and nearly 8,000 educators contributed reports.

The scientific result was undramatic: preliminary figures put germination at 73.8 percent for the space seeds and 70.3 percent for the Earth-stored controls. Analysis in the final report suggested that space-exposed seeds sprouted slightly faster and grew faster at first, but the early lead faded after about four weeks. Many individual reports showed the Earth seeds sprouting first, and the report itself reminds readers that most of the data came from novices.

Hunting for mutants, and a scare about poisonous fruit

Students raised on science fiction went looking for mutants, and some were disappointed because Rutgers California Supreme is a relatively stable tomato. Education Week reported in 1990 that the control plants would help students separate ordinary variation, such as shades of green, from real mutations such as oddly shaped fruit. Park Seed's Jim Alston said the company would look into a call about anything as odd as a blue tomato, though it never expected a commercially promising new strain.

A Los Angeles Times article warned that mutated seeds could yield poisonous fruit, and by mid-April 1990 NASA was publicly pushing back. William Kinard, chief scientist for the LDEF program, said there was no validity to the idea that the seeds endangered schoolchildren. He compared the risk to advising people to stay out of their yards for ten years in case a meteorite hits them. Before approving the experiment, NASA had asked the Agriculture Department to evaluate the safety of the seeds, and the USDA found no food-safety risks. The warnings prompted more student questions, and the final report says that pursuit deepened their understanding of genetics and radiation.

Some of what students reported was harder to interpret. Many described deer, rabbits, ferrets and even moose eating the Earth-based plants while leaving the space-exposed ones alone or barely nibbled. In one case, seeds from a flower with a variegated calyx grew into albino plants, while seeds from a green-calyxed flower on the same plant grew green. NASA's abstract calls such cases mutations assumed to be caused by radiation. The report adds that students saw variation in the Earth-based controls too, which is exactly why controls exist.

Gardens in trenches and high-rise windows

The growing sites show how far the project spread, from greenhouses and freshly tilled gardens to trenches, bags of potting soil and a converted playground. Off-site gardens ranged from large fields to containers on patios and in the windows of high-rise apartments. Local businesses donated materials and labor, and grandparents and other older citizens often supplied the gardening expertise. One elementary class built a robotic watering system, and several secondary classes developed hydroponic growing setups.

A second-grader in Ontario named Matt wrote to NASA that the Earth seed never came up and the space seed grew, then fell off the desk and died. One elementary teacher reported that students wrote stories as well, from factual journals to fiction about aliens living in the seeds. The teacher added that the project felt real because neither teachers nor NASA knew the results, unlike the usual classroom experiments contrived to prove something already known.

What the experiment could and couldn't show

Almost half of the participants who returned data booklets said they would continue with second and later generations. Student researchers also concluded that space might be a secure place to store seeds of endangered plants and food crops, away from the unpredictable conditions on Earth. That conclusion came from a classroom tomato study, so it reads better as an idea than as a finding. The report itself places the main value in the scientific process, meaning the observing, measuring, classifying, interpreting and communicating that students practiced.

One secondary teacher, quoted in the report, judged six years of radiation above the atmosphere to be negligible. A small classroom where 100 students come and go to check and water plants, the teacher added, was a greater danger. The remark is funny, and it points at a real data problem, since plants were often neglected, fussed over, measured and moved around, which left records incomplete. Even so, the report reaches a plain conclusion: space-exposed and Earth-stored seeds differed very little, and thousands of classrooms had checked that with their own plants.