Seed packet terms: hybrids, heirlooms and GMOs

It’s time to start planning the garden for next spring. Your mailbox is full of seed catalogs, and your local nursery is displaying racks and racks of seeds. But the seed packets and catalogs have terms you’ve never heard of before. What do these terms actually mean?

The first important distinction on the seed packet is the difference between hybrid plants and open-pollinated plants. Hybrid plants are produced by cross-pollinating genetically distinct plants, either different species or plants of the same species with different traits. Natural hybrids can occur, but most commercial crops are produced by controlled cross-pollination. Hybrids were created to improve the characteristics of the plants: prettier or bigger flowers; plumper seeds; or bigger fruits, shoots or roots. The original rose, potato, tomato and squash were much smaller than present-day varieties. By selective cross-breeding over hundreds of years, higher yields and tastier crops have been produced.

What is an F1 hybrid? An F1 hybrid is produced by cross-breeding two pure-bred plant lines that have certain desirable traits. F1 refers to the first-generation offspring, which exhibit the desirable characteristics of both parents. The terms “F1 hybrid” and “hybrid” are often used interchangeably in the seed industry. F1 hybrid plants become a problem if you want to collect seed for the following year’s crop. Seeds from F1 hybrid plants will not reproduce true to the parent plant, and the offspring will be less vigorous. If you want to try seed-saving, do not buy F1 hybrid seeds. Instead, buy open-pollinated seeds in which pollination occurs by wind or insects, and is not restricted or controlled.

Open-pollinated plants produce seeds with characteristics similar to the parent plant. A popular type of open-pollinated seed is heirloom. Heirloom seeds are varieties of a particular plant that are at least 50 years old (also described as introduced prior to World War II). These seeds produce plants that remain stable in their characteristics from year to year but can have variation in harvest time and fruit size. Heirloom seed packets commonly list the location or person who has kept the heirloom variety going for many years. Avid heirloom-seed users believe they are not only growing a great plant variety, but they are also helping maintain genetic diversity and keeping a historical connection to their food.

The newest buzz word showing up on seed packets and in seed catalogs is “non-GMO.” GMO stands for Genetically Modified Organism. A Genetically Modified Organism is a plant or animal whose DNA has been altered using biotechnology so that the organism contains a new gene or new combinations of genes that provide improved traits. Can you buy GMO seed at a nursery or garden center? No. GMO seeds are sold only to farmers by the biotechnology company that produced them. The farmer has to sign a technology use agreement that communicates what can and cannot be done with the seed. Are hybrid seeds the same as GMO seeds? No. Hybrid seeds are produced by cross-pollinating rather than using biotechnology.

Many seeds also have organic certification. This is a federal certification that requires that the seeds were grown in very stringent conditions, with limited pesticides and other inputs. Certified organic seed must, by federal definition, be non-GMO. For more information on organic standards, go to the U.S. Department of Agriculture’s Organic Standards website,


Melody Hefner is the Urban IPM and Pesticide Safety Education Program coordinator for University of Nevada Cooperative Extension. Have a gardening question? Ask a Master Gardener at