By Nancy Castaldo
Wheat, maize, rice ... repeat. Those three starchy plants provide about half of all the calories we consume. What's more, of the 12,000 plant species that can be used for human food, only about 150 are cultivated. And that heavy reliance on a limited number of crops poses a serious risk when it comes to our food security. We can look back to the devastation of the Irish potato famine to see the importance of crop diversity. A million people died because a blight killed just one species of potato—the Irish lumper.
According to the Food and Agriculture Organization (FAO) of the United Nations, 75 percent of plant genetic diversity has been lost since the 1900s, when farmers started to grow crops that would offer greater yields and more salable produce. Large, mechanized farms churning out staple grains (much of it going toward feeding livestock) replaced many small family farms that had grown a much wider array of fruits and vegetables. Monoculture depleted soil nutrients and contributed to soil erosion. This led to overdependence on chemical fertilizers, insecticides and herbicides, resulting in the decline of the bumblebees and other pollinators so critical to maintaining our food supply. Other factors have also contributed to the loss of agrodiversity, including our changing climate, which has brought about increased droughts that damage soil quality and rising sea levels that infiltrate croplands with saltwater. An uptick in floods and high-intensity storms also impacts the types of crops farmers are able to plant.
In the U.S., the overall trend in crop species diversity continues to track downward, but there is some hope for a small-farms revolution. And urban gardens are reviving an interest in homegrown crops for communities long underserved by our food system. Here's how you too can be a lifeline for plant biodiversity―at the market, in your backyard and even on your bookshelf.
Nurture Your Own Seeds.
You don't need a lot of land to grow your own fruits and vegetables. The National Gardening Association reported that 35 percent of all U.S. households grow food at home or in a community garden, with significant increases occurring in urban areas. If you're still working on your green thumb, community gardens are a great place to get started, since they offer both space and a group of gardeners to consult as you experiment with different seed varieties. Try saving some of your seeds from your favorite crop to plant again or share with another gardener.
There are so many wonderful, tasty heirloom varieties just waiting to be discovered. You may happen upon a special bean that has been passed down through your family for generations, or find out that your favorite watermelon variety at a local farm stand originated from an heirloom seed catalog. Heirlooms might surprise you. They might show up as a purple carrot, a yellow tomato or a tiny pink strawberry. You might never see these varieties in a supermarket, but there are plenty to be found at your neighborhood farmers' market.
Heirlooms are also critical to our food security. They contain genes distinct from those in the plants grown as monocrops, which risk dangerous collapse should a pest or disease outbreak strike. (For evidence, look to the banana industry, which has long revolved around a couple of commercial varieties. It nearly collapsed after a fungal disease spread in the 1950s and '60s.) By planting, sharing and enjoying heirloom varieties, we keep them around and preserve agrodiversity. And that heirloom might turn out to be resistant to a disease we don't even know about yet.
Hold a Seed Swap.
Seed swaps are a great way to spread some heirloom love. A seed swap is similar to a book swap. For every packet a gardener brings, he or she can pick one to take home. Many gardeners have plenty to share. To get your community involved, conduct some local outreach to ensure you reach a broad audience. Set up some rules: All seeds should be labeled, and they must be viable. Encourage participants to pack their favorite recipes with their seeds. Don't forget to include heirloom flower varieties in the swap too—you'll be supporting the local pollinators that, in turn, support local food production. If you have any leftover seeds at the end of your swap, donate them to a school or community garden.
Visit a Seed Library.
Some public libraries have gotten into the act of seed saving and swapping by hosting "seed libraries" from which you can check out a packet of seeds, just as you would a book. To keep seeds circulating, members take home seeds to cultivate, let the plants flower and drop their seeds, and then return those seeds to the library to share with other gardeners. Not all seeds can be saved year after year—commercial "hybrid" seeds do not produce offspring that are true to the parent plants, and in fact some of them are engineered to be sterile. But heirloom plants can be saved year after year, and these are the varieties you'll typically find in a lending library. Many seed libraries also sponsor talks and gardening tips for their patrons.
Create Your Own Herbarium.
An herbarium is, basically, a scrapbook of plants that have been pressed and preserved. These have been kept by individuals for centuries, and not only by botanists. Experimental composer and musician John Cage, an amateur mycologist, collected important fungal specimens that are now included in the New York Botanical Garden's William and Lynda Steere Herbarium.
Dried plant samples can supply important data of many kinds. For example, in 2013, molecular biologists with the Max Planck Institute for Developmental Biology discovered the identity of the plant pathogen that caused the Irish potato famine. The researchers used plants housed at Munich's Botanical State Collection and London's Kew Gardens; although they were 120 to 170 years old, the specimens nevertheless had many intact pieces of DNA for scientists to decode. Their work has helped us understand how plant pathogens evolve and how human activity impacts the spread of plant diseases.
Historically, herbariums have comprised pressed, dried specimens. To prepare your samples in this manner, press the plant matter in a large book or between sheets of newspaper and place a weight on top. When the leaves are dry, mount them in an acid-free scrapbook to preserve them, and label each specimen on the page. You can also include illustrations, photographs, seed packets and notes. Seed saving is something humans have done for as long as we've grown crops, so think of your project as a means of carrying on an important tradition—as well as a potentially important safeguard for future generations.
Nancy Castaldo has written books about our planet for over 20 years. Her book, The Story of Seeds: From Mendel's Garden to Your Plate, and How There's More of Less To Eat Around The World, earned the 2017 Green Earth Book Award, Sigurd Olsen Nature Writing Notable book, and was a Junior Library Guild Selection. Her latest is Back from the Brink: Saving Animals from Extinction. Her research and photography has taken her all over the world from the Galapagos to Russia, and she loves sharing her adventures with her readers.
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