A mudroom is designed to take care of this problem, but somehow it doesn't. Our mudroom has a mudroom, complete with a steel grate in a recessed box to catch boot scrapings. But still the soil follows us in like a faithful pet, on dusty socks, in our pockets, on the roots of freshly dug leeks.
An odd rule of modern life teaches us that the boundary between a sanitized interior and the fertile but unruly world of nature must not be bridged. I admit that I am more comfortable in a clean home. Does some kind of fear underlie my discomfort with its opposite, or am I just attuned to an aesthetic of gleaming wood and tile?
A lengthening thread of intriguing research, sometimes called the hygiene hypothesis, posits that we'd be a lot healthier if we weren't so clean. Because we wash so much, clean our houses with too-powerful stuff and, most important, don't spend enough time outdoors, we're missing out on our share of beneficial bacteria, parasites, molds and miscellaneous microbes that our bodies need for our immune systems to develop.
This is why, the theory goes, children today have so many allergies and excessive autoimmune responses. The healthiest, some studies show, are those who grow up in large families, on farms, with lots of animals about. Surely it wouldn't hurt to get kids outside more, away from their computer screens, to make mud pies.
It's not that good sanitation isn't important, but that we have taken it too far. Overuse of antibiotics to treat ourselves and the animals we eat has produced resistant "superbugs." Attack one problem with a blunt instrument, ignoring the subtleties of the natural world, and a bigger one will always bite you back.
I'm looking forward to what might be discovered in this relatively new field. I still haven't read Jessica Snyder Sachs's 2007 book "Good Germs, Bad Germs: Health and Survival in a Bacterial World," but it seems like a good place to start. In the meantime, look for me outside, playing in my giant sandbox and healthier for it, even though I wipe my feet on the way back in.
email@example.com Damrosch is a freelance writer and the author of "The Garden Primer."
gRead month-by-month tips from Higgins (such as removing winter weeds in January) and more of his columns at washingtonpost.com/home.
6Read more about growing your own food at washingtonpost.com/vegetablegardens .