They haven't found any little green men, but NASA is excited about a different green discovery on the red planet.

Martian dirt was apparently good enough for asparagus to grow in, NASA scientists said yesterday.

Announcing the results of an analysis of soil collected by the Phoenix Mars lander, Prof Samuel Kounaves, the project's lead chemist, said: "There is nothing about the soil that would preclude life. In fact, it seems very friendly. The soil is the type in your back yard. You may be able to grow asparagus very well."

The analysis is based on a cubic centimetre of soil scooped up by the lander's robotic arm and introduced into one of its eight ovens, where it was gradually heated up to 1000C.

Prof Kounaves said his team was "flabbergasted" at the results: "We have found what appears to be the requirements of the nutrients to support life, past, present or future," he said.

Scientists found elements in the soil that included magnesium, potassium and sodium.

"There are probably other mineral species, we are still working on data," he said.

Prof Kounaves said the analysis results are "more evidence that there was water action at some point on Mars".

"It's very similar to the soil results we got from some dried places on Earth. That's the exciting part," he said.

The sample is from surface soil that scientists confirm covers a layer of ice.