All posts by Lisa Dermer

Heirloom Gardening for Biodiversity

We all know biodiversity is a good thing. But how does gardening with heirlooms promote biodiversity? And how can you garden with biodiversity in mind?

We think of biodiversity on three levels: genetic, species, and ecosystem. All three apply to your garden or farm, no matter its scale.

Heirloom Vegetable Genetic Biodiversity
Pungo Creek Butcher dent corn, Yellow Fleshed Moon & Stars watermelon, Cosmic Purple carrot
Genetic Diversity

  • Heirlooms may carry genes that provide disease resistance or other useful traits we don’t even know we need.  Preserving heirloom varieties maintains this “gene bank” as insurance against future plant diseases or other threats.
  • Genetic variation within a planting gives that crop resiliency to cope with the unexpected – we may lose some plants, but we can build stronger varieties by saving seed from those that survive. To maintain diversity within a variety, we save seed from a large number of plants.
  • Traditional plant breeding with open-pollinated (OP) varieties builds biodiversity by creating new genetic profiles with each generation.  It also allows us to explore unexpected mutations – with plants, mutations often aren’t bad.  A mutation is simply a shift in the genetic code, sometimes with unexpectedly good results.

Species Biodiversity Mixed Herbs and Vegetable Production
Mixed herb and vegetable production.
Species Diversity

Just growing a lot of different kinds of plants creates species diversity in your garden.  But you may not be aware of all the benefits you’re getting. Ecologists correlate species biodiversity with productivity. That means more diverse systems produce more biomass.  And that means more veggies for your table!

Many modern varieties are bred for monoculture conditions.  Heirlooms are already adapted to gloriously biodiverse, ecologically grown gardens, like those of our ancestors.

And biodiversity of one type, like the plants in your garden, tends to come along with increased biodiversity of other species, like beneficial insects and micro-organisms in your soil – which compete with or prey upon garden pests and help control their populations.

Tan Cheese Pumpkins
Tan Cheese and other Moschata types thrive where other winter squash succumb to pests and disease.
Ecosystem Diversity

Your garden is unlike anyone else’s.  Celebrate it!  Instead of trying to grow things that aren’t suitable for your garden, seek out what is uniquely adapted to where you live.  You may find that you don’t miss growing Buttercup winter squash – which may not handle pests in the Southeast – because you can grow sweet, long-storing Seminole pumpkins – which don’t produce well in areas with cool nights.

Rather than bemoaning a garden that doesn’t fit the commercial “ideal,” seek out the heirlooms that have been developed over generations, right where you live.  Ecosystem diversity creates what foodies call “terroir” – the food grown where you live is unlike food grown anywhere else.

Who is Gary Nabhan? Chile Peppers and Place Based Foods

habanero peppersThe authors of the new book Chasing Chiles: Hot Spots Along the Pepper Trail singled us out as a force working for the preservation of heirloom chiles in a recent interview on grist.org – Hot stuff: chile peppers, climate change, and the future of food. Authors Kurt Friese, Gary Nabhan, and Kraig Kraft (an ethnobotanist, a chef, and an agroecologist) examine climate change through the lens of the chile pepper. In another grist post, Nabhan writes about Global weirding and the scrambling of terroir.

We carry seeds for three of the chiles they track in the book – Habaneros (the Yucatan), Fish Peppers (Chesapeake Bay area) (sold out for this year), and Jimmy Nardello’s (from Italy via Connecticut). 

Gary Nabhan will be presenting at this year’s Heritage Harvest Festival on the findings of the book.  You can download free booklets on Place Based Foods from his website. The most recent – Appalachia – From Rarity to Community Restoration and Market Recovery – features a piece on heirloom grinding corns of Appalachia by our own Ira Wallace, as well as articles on heritage apples, pawpaws, wild spring greens, traditional sweet potato curing, and Bill Best of Sustainable Mountain Agriculture Center on the Noble Bean.

Why we wait to thin corn plants (‘til 4 inches!)

Information in this post comes from and is inspired by the new book The Resilient Gardener by Carol Deppe.

Corn Seedlings

Some gardeners and farmers don’t thin corn at all. But sowing extra seed ensures a uniform stand of corn (especially important for small plantings) and allows us to select for seedling vigor. Thinning gives us plants with better disease and pest resistance, producing earlier, larger ears. For seed savers, selecting the best plants is essential not just to improving a variety, but also to simply maintaining it.

It’s too easy to put off thinning a stand of corn until the plants are a knee-high jungle, competing for light, water, and other resources. But thinning corn just after the plants emerge isn’t in our best interests as gardeners or seed savers either. Ideally, we wait until the plants are about four inches tall.

Why not simply keep the very first plants to pop up? Because these are not necessarily the first seeds to germinate. Many old-time, open pollinated heirloom corns put more energy into their roots initially, before sending their shoots upward. And we love this about them. It means they have bigger, better established root systems when the tender seedlings become vulnerable above the soil. And if the plants get nibbled on or otherwise set back, they can recover much more easily. If we were to select the first plants to emerge, we’d be selecting against this very useful trait.

Additionally, until the plants are about two inches above the ground, they’re still growing off the food reserves in the seed. And that depends on the size of the kernel – which is mostly determined by its location on the ear and the genetics of the mother plant, not on the seed genes. Once the corn seedlings reach four inches tall, we can compare their vigor based on their individual genetic profiles.

So as much as you may hate to watch those extra corn plants creep ever taller before you ruthlessly tear them from the earth, we trust you’ll do the right thing. Wait until your corn seedlings are four inches tall to accurately choose your most vigorous plants. You’ll be helping keep these old-fashioned varieties as hardy and productive as our forebears bred them to be.