Features Fruit Production
Low maintenance strawberry may be good for space

May 6, 2010 — Astronauts
could one day tend their own crops on long space missions, and Purdue
University researchers have found a healthy candidate to help satisfy a sweet
tooth – a strawberry that requires little maintenance and energy.

May 6, 2010 — Astronauts
could one day tend their own crops on long space missions, and Purdue
University researchers have found a healthy candidate to help satisfy a sweet
tooth – a strawberry that requires little maintenance and energy.

Cary Mitchell, professor
of horticulture, and Gioia Massa, a horticulture research scientist, tested
several cultivars of strawberries and found one variety – Seascape – that seems
to meet the requirements for becoming a space crop.

“What we’re trying to do
is grow our plants and minimize all of our inputs” Massa said. “We can grow
these strawberries under shorter photoperiods than we thought and still get
pretty much the same amount of yield”

Seascape strawberries are
day-neutral, meaning they aren’t sensitive to the length of available daylight
to flower. Seascape was tested with as much as 20 hours of daylight and as
little as 10 hours. While there were fewer strawberries with less light, each
berry was larger and the volume of the yields was statistically the same.

“I was astounded that even
with a day-neutral cultivar we were able to get basically the same amount of
fruit with half the light,” Mitchell said.

The findings, which were
reported online in the journal Advances in Space Research, showed that the
Seascape strawberry cultivar is a good candidate for a space crop because it
meets several guidelines set by NASA. Strawberry plants are relatively small,
meeting mass and volume restrictions. Since Seascape provides fewer, but
larger, berries under short days, there is less labour required of crew members
who would have to pollinate and harvest the plants by hand. Needing less light
cuts down energy requirements not only for lamps, but also for systems that
would have to remove heat created by those lights.

“We’re trying to think of
the whole system – growing food, preparing it and getting rid of the waste,”
Massa said. “Strawberries are easy to prepare and there's little waste.”

Seascape also had less
cycling, meaning it steadily supplied fruit throughout the test period. Massa
said the plants kept producing fruit for about six months after starting to
flower.

Mitchell said the earliest
space crops are likely be part of a “salad machine,” a small growth unit that will
provide fresh produce that can supplement traditional space meals. Crops being
considered include lettuces, radishes and tomatoes. Strawberries may be the
only sweet fruit being considered, he said.

“The idea is to supplement
the human diet with something people can look forward to,” Mitchell said.
“Fresh berries can certainly do that.”

Judith Santini, a research
statistical analyst in Purdue's Department of Agronomy, was responsible for
data analysis from the tests.

Mitchell and Massa said
they next plan to test Seascape strawberries using LED lighting, hydroponics
and different temperature ranges. NASA funded their work.