It's pretty difficult to make an area inhospitable to all life, including microbial (though I guess massive arsenic poisoning will do it). But as soon as you st

It's pretty difficult to make an area inhospitable to all life, including microbial (though I guess massive arsenic poisoning will do it). But as soon as you start thinking like that, then you wind up with a very boring sliding scale of hospitality for microbes, fungus, weeds, insects...