Question

Can Earth plants grow on Mars?

This question is asked frequently, and now I have some data on which to base a reply. The biggest problems on the surface of Mars are the low temperature and lack of water, and these conditions make it impossible for terrestrial plants to grow there unprotected. But what about plants protected in a greenhouse and supplied with water? The following experimental results were sent by Donald Howk, head of the Science Department at Keystone School in San Antonio, Texas: I would like to tell you about a science fair project from one of my incredible 8th graders, Sasha Rohret. Her project was based on the very simple question whether plants can grow in the martian soil and atmosphere. She carefully designed several air-tight glass tanks to represent miniature greenhouses on Mars, and she obtained soil from a volcano in South America that is close to martian soil in its chemical make-up. She then set up the experiments as follows: Mars air and Mars soil Mars air and Earth soil Earth air and Mars soil Earth air and Earth soil She selected, measured, and photographed 72 lima bean seeds and planted them all in identical cups with a ruler for easy measurement within each tank. The plants grew wonderfully in the martian soil and Earth air, but did not grow at all in the martian soil with the martian air. The plants did not grow in the Earth soil with martian air either. They did, of course, grow in the Earth soil and air, but not as well as the Mars soil with Earth air. She theorized (correctly I believe) that the problem with the Mars air was not the high CO2 levels, but rather the low O2 levels that prevented the plant growth. Sasha Rohret was recognized by the San Antonio Express News and local news channels, as well as in several science fairs.

David Morrison
NAI Senior Scientist, based on a report from Donald Howk in San Antonio
July 8, 2004