A special treat is on the menu for NASA astronauts on the worldwide Space Station on Monday – lettuce.

“It’s fresh.” After toasting their pieces of lettuce together with a quick “cheers”, astronauts aboard the worldwide Space Station took the first bites of food grown and harvested entirely in space. Instead, NASA seeded a rooting “pillow”, which contains the necessary nutrients and dirt for the plants to take root and fully grow in 33 days.

The plants were cultivated for 33 days aboard the ISS and sent back to Earth for safety testing.

The NASA astronauts of Expedition 44, including the one-year resident Scott Kelly, will finally be able to taste the fruits of their labour today (10 August) having spent over a month working on the Veggie system.

The leafy greens were cleaned with citric acid-based, food safe sanitizing wipes, according to NASA.

NASA has been studying how vegetables grow in space and their nutritional value since May 2014.

Astronauts will dine on romaine lettuce grown in a capsule specially created to be a vegetable patch in space.

The Veggie growing system provides lighting and nutrient supply for plants in the form of a growth chamber and planting “pillows”.

Green LEDs emit less light compared to red and blue LEDs; however, to make the veggies appear more appetizing, the researchers doubled the amount of green LED light. It also could be used by astronauts for recreational gardening activities during deep space missions.

“Besides having the ability to grow and eat fresh food in space, there also may be a psychological benefit”, Dr. Gioia Massa, the NASA payload scientist for Veggie, added.

Otherwise the plants would grow purple and might look inedible.

“The Veggie experiment is now the only experiment we are supporting which involves evaluating the effects of plant life on humans in space“, Alexandra Whitmire, behavioural health and performance research scientist for NASA’s Human Research Program, said. “I think that plant systems will become important components of any long-duration exploration scenario”, Dr Massa said.