As large swathes of the Earth’s land area become unsuitable for agriculture, e.g due to salinisation (http://en.wikipedia.org/wiki/Soil_salinity), there is growing interest in finding alternative spaces and places to cultivate plants. And when it comes to locating such sites, it seems that the sky’s not the limit, but the Moon may be. Researchers at the University of Arizona’s Controlled Environment Agriculture Center (CEAC, http://www.uanews.org/node/33901) are investigating whether terrestrial plants could be grown hydroponically on the Moon. This soil-less approach overcomes one of the obvious constraints to lunar horticulture – the lack of soil; the demand for water is to be met from astronauts’ urine (presumably generated by the water they drink, but which still begs the question of where all the water ultimately comes from). And to avoid other typical dangers to living things on the moon – e.g. deadly cosmic rays, micrometeorites, and solar flares – the greenhouses would be buried underneath the Moon’s surface. This would also protect the plants from any harm caused by proximity to terrestrial Wi-Fi networks (http://www.physorg.com/news/2010-11-dutch-wi-fi-possibly-trees.html). And if we ever get as far as growing apples or pears on the Moon, it will be interesting to examine the work of Peter Barlow and colleagues on the effects of lunar tides on stem diameter of trees grown in situ (Protoplasma 247:25–43, 2010). Whilst the CEAC’s investigations are unlikely to solve the Earth’s pressing cultivation problems, such work is considered important to achieving sustainable living on the Moon (if we ever go back there . . . probably when we have to flee the Earth and set up home elsewhere because we’ve totally ruined our home planet’s capacity to grow fruit and veg!), or elsewhere in the solar system. Still, one positive from all of this should be that we might learn how to grow cereals to make biscuits, which would be ideal to accompany the cheese that’s apparently already up there (http://en.wikipedia.org/wiki/The_Moon_is_made_of_green_cheese). Mind you, I dread to think what the food miles (http://en.wikipedia.org/wiki/Food_miles) would be if such extraterrestrials try to export their produce to Earth-based supermarkets!