Flipping through your favorite gardening magazine or browsing a gardening website, you start reading about the horrors of GMO seeds. Organic gardeners exhort readers to plant only heirloom seeds, while the latest seed company that lands in your mailbox trumpets the new hybrids on the market. What do these terms mean?

This simple Gardener's Guide to Seed Terms should help you navigate the major descriptive terms for seeds.

Heirloom Seeds

The term heirloom, unfortunately, has no set definition among gardeners. Typically gardeners call any seed variety that's been around for more than 50-60 years an "heirloom" seed. Heirloom seeds are usually open pollinated, meaning that wind or insects fertilize the seed. They'll breed true to their parent plants, so if you harvest seeds and replant them you should get the same variety.

Heirloom seeds may not be organically grown. That's an important distinction for gardeners. Often people equate the term "heirloom" with an organic seed product. While there are certainly organic heirloom seeds, just because a package is marked heirloom doesn't mean it was grown using organic gardening methods.

Why choose heirloom seeds? Flower enthusiasts love the rich varieties and colors that harkens back to yesteryear. If you live in an older home such as a Victorian home, it can be fun to recreate a Victorian garden using varieties your grandmother and great grandmother would recognize. For vegetable and herb growers, the beauty of heirloom seeds is in the wide variety of tastes, colors and textures of edibles produced by these plants. Large-scale agribusinesses typically plant only a small handful of seed varieties, choosing vegetables that mature quickly into a uniform product that transports well. Flavor is often sacrificed to create such a vegetable. Witness the dry, hard as a rock tomatoes in the markets in January; they're pale shadows of a juicy heirloom Brandywine tomato, a circa 1886 variety. It's a wonderful tomato, but very slow maturing, and therefore not commercially grown. But backyard gardeners love to experiment, and with seed packages costing only a few dollars, you can easily try your hand at many heirloom vegetables and explore the rich and diverse world of older varieties. 

Hybrid Seeds

People seem to think that hybrid seeds are something new fangled and fearful, but in truth humans have been hybridizing seeds probably as long as agriculture has been around. Hybrids are nothing more than plants created by human intervention, or the intention pollination of plants to obtain a desired outcome. Hybrid seeds are the most plentiful for home and commercial use. They're bred for many beneficial characteristics such as disease and insect resistance, new flower types, improved vitamin content in vegetables and grains, and many other characteristics. There's nothing inherently bad with hybrid seeds; the only drawback is that seeds collected from hybrid plants are either sterile and won't sprout, or the offspring grown from such seeds doesn't resemble the parent plant. 

Genetically Modified Seeds (GMO)

Genetically modified seeds are also manmade seeds, but with a difference. In GMO seeds, new genetic material is inserted into a plant to create new plants with desirable characteristics. These seeds are highly controversial. In some parts of the world, they are outlawed. And while the "official" word from the U.S. government is that such seeds are safe, contradictory evidence indicates otherwise. An article in the summer 2009 issue of the Price Pottenger Nutrition Journal, for example, quotes extensively from U.S. Department of Agriculture and other published reports warning that GMO crops may alter the genetics of bacteria residing in the human gastrointestinal tract. These GMO crops are designed to be resistant to dangerous pesticides like Roundup,These bacteria are responsible for digestion and keeping so-called 'bad' bacteria that causes disease at bay. Many question the push to use GMO seeds. Although some farmers prefer such seeds, new studies are showing that the past 30 years of using Roundup on GMO crops have brought on a new breed of super weeds, which farmers are treating with even more pesticides. Needless to say, GMO seeds are highly controversial and are best avoided by the home gardener and eater! 

What seeds should you choose for your garden? In the end, it's up to you. Depending on your gardening interests, you might start with simply hybrid and heirloom seeds. Grow what you like. Gardening, after all, should be fun!