Analysis of the soil has surprised and delighted Nasa scientists
Martian soil appears to contain sufficient nutrients to support life - or, at least, asparagus - Nasa scientists believe.
Preliminary analysis by the $420m (£210m) Phoenix Mars Lander mission on the planet's soil found it to be much more alkaline than expected.
Scientists working on the spacecraft project said they were "flabbergasted" by the discovery.
The find has raised hopes conditions on Mars may be favourable for life.
"We basically have found what appears to be the requirements, the nutrients, to support life, whether past, present or future," said Tufts University's Professor Sam Kounaves.
The researcher is the "wet chemistry" lead on the spacecraft's Microscopy, Electrochemistry, and Conductivity Analyzer (Meca) suite of instruments.
Although he said further tests would have to be conducted, Professor Kounaves said the soil seemed "very friendly… there is nothing about it that is toxic".
"It is the type of soil you would probably have in your backyard - you know, alkaline. You might be able to grow asparagus in it really well."
As well as being far less acidic than anticipated, the soil was also found to contain traces of magnesium, sodium, potassium and other elements.
"We were all flabbergasted at the data we got back," said Professor Kounaves. "It is very exciting for us."
The analysis is based on a cubic centimetre of soil scooped from 2.5cm (one inch) below Mars' surface by the lander's robotic arm.
The sample was then tested using a technique that involves mixing the soil with water brought from Earth and heating the sample in one of the lander's eight ovens.
After a 10-month flight from Earth, Phoenix touched down successfully on Mars' northern plains on 25 May.
The Arctic location where Phoenix landed is thought to hold large stores of water-ice just below the surface.
Last week, scientists said they were positive there was ice at the landing location after eight dice-sized chunks were seen to sublimate (turn straight from solid to vapour) away in a series of photographs.
Phoenix is undertaking a three-month study of Mars' geological history