I follow Shean down a flight of stairs to his apartment’s garage. It’s where, in another bin, he stores the worms’ work after harvesting a sufficient quantity. When he opens the bin, the castings look like rich farm soil. Shean rolls a bit in his fingers. “It’s nice and crumbly,” he says. “ ‘Black gold’ is what the vermicomposters call it.” By now, Shean has removed as many of the worms as possible. “The last time I emptied the bin upstairs,” he continues, “I took out handfuls of worms. There were probably 1000 in the bin. But you can’t get them all. And there are their cocoons, little footballs a couple of millimeters across, that are hardly detectable at all. They hatch later. But the worms that are still in here now don’t have much to eat.”
Shean thinks of Southern California as a perfect place for vermiculture, especially in comparison to his home state of Maryland. He had a garden when he was a kid, he tells me, and then composted in Providence, Rhode Island, while he attended Brown University. “You have to provide lots of packing and bedding for insulation around an outdoor compost bin on the East Coast. For a while, I kept an indoor compost bin on my kitchen floor. And it’s harder getting the worms there. A couple of years ago, the post office made it illegal to send live animals through the mail.”
Shean came to San Diego a year ago to work with Malin Space Science Systems, a company that makes cameras for use on robotic spacecraft. He has a master’s degree from Brown in geology and follows what one of four cameras on the Mars rover picks up. “Since there is no vegetation on Mars, it’s perfect for looking at geological formations,” he says.
Could wiggler worms do their thing on Mars, I ask? Shean laughs and says it would be much too cold for them. “But here,” he goes on, “it’s easy to get started in vermicomposting. I bought my worms for $25 a pound from a place up in Carlsbad. But a person could get started by just taking a handful from someone who has them. They reproduce very fast.”