The Little Pot With a Big Footprint

What does a book about cannibalism, civilization and the rise and fall of human societies have to do with a seed-starting pot?

More than you might think.

One of the ideas in Marvin Harris's Cannibals and Kings is that abundance has a cost.

Harris gives a striking example: 2,790 calories of energy are used to produce and deliver a can of corn containing just 270 calories of food.

Our modern society can sustain that kind of staggering energy deficit because we have been burning through a massive, nonrenewable inheritance: fossil fuels.

EROI — energy return on energy invested — asks how much usable energy we get for the energy required to obtain it.

Consider the seed-starting pot.

There are now pots made from peat, manure, seaweed, paper, coir, rice hulls and various plant fibers. The material is often the first thing we compare. (Read my post comparing different seed-starting systems here.)

But what did it take to turn that material into a pot?

The Material Is Only the Beginning

Take peat.

Peat is an accumulation of partially decomposed plant material formed over thousands of years in wetlands. Peatlands also store enormous amounts of carbon and provide important habitat and water-regulation functions.

Ancient bogs are drained, stripped of vegetation, and milled. The peat is left to dry, collected, and transported to be processed into pots.

Thousands of years to form. Machines and fuel to extract.

The Pot Made From a Waste Product

CowPots are made from composted cow manure collected from dairy farms.

It sounds almost perfect: take a waste product and turn it into something useful.

At Freund's Farm in Connecticut, where CowPots were developed, the manure first goes through a methane digester that captures biogas for heat. It is then separated, composted and processed into the material used to form the pots.

A waste product with a digester, a separator, and a dryer.

The Seaweed Question

Ocean Made makes pots from seaweed and recycled plant fibers.

Seaweed seems like the obvious answer. It's highly renewable and can be grown without using agricultural land.

But seaweed arrives wet — fresh seaweed can be about 90 percent water. Turning it into a useful material requires drying and processing, and those steps take energy.

The material may be renewable. That doesn't mean the process is free.

Even Paper Has a Story

Paper seems simpler.

Some paper pots are made from recycled paperboard and formed into individual containers. Botanical Interests, for example, uses 100% recycled food-grade paperboard.

Others take a more elaborate approach. The thin kraft paper used in paper chain pots is specially processed to withstand wet conditions, then formed into an accordion or honeycomb structure held together with adhesives.

How much transformation was required to get from the original paper to the finished object?

A seed-starting pot holds soil, supports a seedling and carries that seedling safely to the garden.

What if all we need to do is change the shape of the paper?

And I might have an idea.

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