Inflation Gets Right Down to the Real Nitty-Gritty

What does it have? Depends on the recipe, but any kind of topsoil or potting mix is likely to be crammed with composted organic material. Topsoils can be made from composted shellfish shells, for example. Potting mixes often contain sphagnum peat moss from bogs in Canada or Ireland. Bark fines might come from a sawmill in the Deep South. Coconut "coir," a peat moss substitute, gets shipped all the way from Asia.

A common ingredient in potting mixes is perlite, which makes the soils airier while also retaining moisture. In its final form, small white pellets, it appears to be something synthesized in a factory. In fact, it comes from a volcanic sand mined on the Greek island of Milos. Shipped to the United States, the ore is heated to 1,400 degrees Fahrenheit, at which point it pops into kernels.

Different companies have different recipes, with some variation depending on local materials.

"Just like making a cake. One hopper has peat moss in it, one hopper has perlite, one hopper has bark, several hoppers have fertilizer and limestone," said Steve Jarahian, who until his recent retirement spent more than 30 years concocting potting soil for Fafard in Anderson, S.C.

Dirt has been steadily evolving into "growing media" since the 1960s. Back then, a commercial greenhouse operator might simply have used topsoil. But then the "soil-less" mixtures came along, often known as the Cornell Mixes, after the professors who developed them. They relied heavily on peat moss and either vermiculite or perlite.

Recently, environmental concerns have arisen about the use of sphagnum peat moss, which is "vacuum-harvested" from bogs in Canada. Paul Short, president of the Canadian Sphagnum Peat Moss Association, said that, after being harvested, the bogs are restored to functioning ecosystems: "Our view is we are a renewable resource," he said. Nonetheless, some consumers and companies are switching to coconut coir.

At Johnson's, a customer will find a block of dried coconut coir selling under the brand name "Beats Peat." The package describes it as "the "Eco-Friendly Way to Improve your Soil." Look closely, and you'll see the source: the Republic of Vietnam.

Steve Titko, a director of research and development for Scotts Miracle-Gro, said the industry has tried in recent years to shorten the supply lines and use more local, recycled materials in topsoils and potting mixtures.

Louis, of Sun Gro, said her company has also looked for more local raw materials, but she has high standards: "If they provide the same air capacity, water capacity, nutrients, and structure -- if they will do what we want them to do and provide the performance we're looking for -- we'll look at them."

The rise in the price of dirt reveals how intricately connected the various elements of the consumer economy are. A spike in costs in one sector can have reverberations across the board and into your back yard.

Bark fines, for example, are in shorter supply because declines in the housing market have lowered the production of lumber at sawmills.

"If they're not building homes, if they're not demanding lumber, the sawmills are not producing, and if the sawmills don't produce, we don't get their byproducts," said LaGasse of the Mulch and Soil Council.

Potting mixes often contain chemical fertilizers. The price for fertilizer has risen sharply, in part because fertilizer requires a great deal of energy to manufacture and transport, and in part because demand has spiked. With corn selling for $7 a bushel -- prices driven by the government-mandated and subsized boom in corn-based ethanol -- farmers are planting more crops and demanding more fertilizer.

It may be a sign of the times that even a dirt bag is getting expensive. The typical dirt bag is made of plastic, which comes from oil, which, at last glimpse, was still north of $100 a barrel.

Then there's the cost of the shrink-wrap that surrounds the dirt bags on the wooden pallets.

And the pallets cost more, of course, because wood costs more. Why does wood cost more? Possibly because, with oil, coal and gas prices so high, wood suddenly is more attractive as a fuel source.

"Your plastic bag is, you know, up 10 or 12 cents over what it was last year at this time. Your stretch wrap -- when you see a whole pallet, it's wrapped with plastic -- that's affected. The pallet costs more -- wood's up," Jarahian said. "Everything is related to oil."