Polish seed producer compares seed germination after suborbital flight

Rocket flight is not a conventional stage in seed production. For Polish seed producer TORAF, however, it has become part of a research programme investigating whether short-term exposure to suborbital flight conditions can be associated with measurable changes in seed performance.

In November 2025, around half a million seeds were carried aboard PERUN, a Polish research suborbital rocket developed by SpaceForest. The seeds travelled as dry material and were recovered after the flight. TORAF subsequently compared selected samples with corresponding seed material that had remained on the ground.

The November mission was the first of four planned TORAF seed flights. “The idea is relatively simple: expose dry seeds to unusual flight conditions, bring them back, germinate them under controlled conditions and compare the results with a control sample,” explains Marek Wieroński of TORAF.

A seed company with its own testing capability
TORAF has been active in the seed sector for more than 35 years and operates more than 40 hectares of its own seed-production fields near Kluczbork in south-western Poland. Its activities include vegetable, flower, herb and sprouting seeds, as well as bulk seed, contract packing and private-label projects.

The company also operates its own accredited Seed Testing Laboratory. According to Wieroński, this was an important part of the project because germination and seed-quality assessment are already part of TORAF’s routine work.

“The laboratory work is not something we created specifically for the rocket programme. Seed testing is part of our normal activity,” he says.

The PERUN project therefore introduced a new pre-germination exposure, while much of the subsequent assessment could be carried out using established laboratory procedures.

What happened during the flight?
PERUN reached an altitude of 19.3 km during its 22 November 2025 flight. The complete mission lasted 277.2 seconds.

According to him, the seeds did not germinate during the flight. Instead, they remained dry inside the payload and were exposed to the changing conditions associated with launch, flight, and recovery.

Pressure in the payload compartment fell to approximately 70–90 hPa, while the temperature remained between 7.5°C and 10°C. The payload was also exposed to vibration and changing acceleration.

“The experiment is not about growing tomatoes or radishes inside a rocket. The question is what happens when the seeds are exposed to the flight environment and are then germinated under controlled conditions.”

One sample flew, one stayed on the ground
The experimental design was based on a straightforward comparison: one group travelled aboard PERUN, while a corresponding control group remained on the ground.

For each species or variety included in the laboratory comparison, TORAF tested 400 post-flight seeds and 400 control seeds. The control material was stored under monitored conditions at 10–15°C and 30–40% relative humidity.

Both groups were subsequently assessed using the same laboratory criteria. These included normal seedlings, abnormal seedlings and dead seeds, as well as observations of early seedling structures such as the primary root and cotyledons.

“The material was unusual, but the assessment had to remain consistent,” Marek shares. “We used the same evaluation criteria for the post-flight material and the controls.”

First results show different responses
The initial results do not show one common response across the tested species.

Garden cress produced 92% normal seedlings after the flight compared with 93% in the control. Radish ‘Flamboyant 3’ recorded 85% compared with 84%, while crimson clover recorded 94% normal seedlings in both groups.

Other samples showed larger differences. Tomato ‘Bajaja’ produced 80% normal seedlings after the flight compared with 88% in the control. The proportion recorded as dead was 9% after the flight and 3% in the control.

Broccoli Raab produced 88% normal seedlings after the flight compared with 94% in the control, while dead seeds accounted for 9% and 3%, respectively. Alfalfa recorded 79% normal seedlings after the flight and 83% in the control.

The results therefore include samples with relatively little difference as well as samples showing differences in germination performance or early seedling development.

A difference does not establish a cause
Wieroński stresses that the first results should be treated as observations rather than evidence of a specific flight effect.

“Seeds are biological material, and variation can occur even between samples from the same seed lot,” he says. “A difference observed after one flight is not, by itself, an explanation of why that difference occurred.”

This is also why the programme was designed around four flights. Additional missions will provide further samples and controls that can be compared with the results from the first flight.

“If similar responses appear repeatedly in the same species, they become more interesting for further investigation. If they do not repeat, that is also useful information,” Marek adds.

For TORAF, the November flight therefore provides a baseline rather than a conclusion.

Looking beyond germination
The research programme extends beyond TORAF’s standard germination assessment. Researchers from Jagiellonian University Medical College are analysing sprouts produced from the experimental material, including their phytochemical composition.

Researchers from the University of Silesia are also studying plant development, including work with Arabidopsis thaliana and tomato.

“One of the questions is whether differences, if they occur, can also be observed at later stages of plant development.”

This distinction is relevant to controlled-environment agriculture. Germination provides an early measure of seed performance, but it does not necessarily predict subsequent plant growth, morphology or biochemical characteristics.

Four flights, rather than one answer
The remaining three planned flights are intended to provide additional data and improve the basis for comparison.

“We are not looking for one result from one flight. The purpose of the programme is to collect comparable data over several flights.”

For TORAF, the project combines an unusual environmental exposure with familiar seed-testing principles: defined seed material, a control group, controlled germination conditions and consistent assessment criteria.

The first flight has already produced several measurable differences, alongside samples where post-flight performance was very similar to the controls. The next stages will help determine whether any of these observations are reproducible.

“The first flight gives us the starting point. The next flights will tell us much more about whether the observations can be repeated.”

For more information:
TORAF
Marek Wieroński
[email protected]
https://toraf.pl/