Seed Packages 101 – Seed Terminology Made Simple(r)

So just what is the big deal about an “heirloom?” What is the difference between that and an F1 hybrid? What about GMO?  Seed packages often include terms such as “heirloom” or “F1 hybrid.” These terms are quite precise, but may be used incorrectly by gardeners. There are also a number of misconceptions about these terms.

Plain Language Seed Package Terms

Consider this guide a plain-language “go-to” resource. Seed and plant choices abound, and gardeners deserve to make educated decisions about what is best for their own use. This is an introduction to some of the more common terms you are likely to encounter. Look for Seed Packages 102 appearing on the free Gardening With Soule here soon.

Want more? On my Gardening With Soule membership site I have gone into greater detail with an extended discussion of GE and GMO’s. There is also a printable PDF guide, and a series of videos – all about the seeds of vegetables and flowers that you may wish to grow.

Here the cultivar name is Cherries Jubilee.


The word cultivar derives from the term “cultivated variety.” A cultivar name is often presented as the ‘variety name’ after the genus and species in home garden seed catalogs. In this example: San Joaquin Pepper (Capsicum annum ‘San Joaquin’), the cultivar name is ‘San Joaquin.’

Described by the International Code of Nomenclature as an “assemblage of cultivated plants clearly distinguished by one or more characteristics, which, when reproduced, retains its distinguishing characteristics,” a seed-grown cultivar can be either a hybrid, and F1 hybrid, an open pollinated variety, or even an heirloom. Read on for definitions of these terms.

In a nutshell, a cultivar is a cultivated variety with specific characteristics or traits.

Open Pollinated (OP)

Open-pollinated varieties of seed are ones that just happen. These seeds result from free pollination by insects, wind, self-pollination, or any other natural forms of pollination. If you save seeds from standard OP open pollinated varieties, and grow them in the following years, they will “come true,” meaning that the plants will produce plants with characteristics or “traits” like the mother (seed making) plant from which the seeds were harvested.

BUT keep this in mind! You may know the mother plant that you are harvesting the seed from – but you may have no idea who the father is. Both the wind and insects can bring in pollen from very distant plants. This may include some undesirable traits.

Because of this, saving OP seed can be a gamble. This is especially true with many common home garden plants, notably squash and pumpkins. Unless different varieties are separated by specified distances, they may exchange pollen or “cross pollinate” each other, resulting in a hybrid – a different finished product than expected.

If you get seed from a seed library, the “easy” or “advanced” on the package is not about growing the plant – it is about trying to save the seed of what you grew and how likely you are to get the offspring to grow like the mother (seed making) parent.

OP Fail

Case in point, I saved seed of my rat tail radishes one year. This is a type of radish where you steam and eat the green seed pods. The radishes themselves can also be roasted and eaten, much like a turnip.

The seeds grew just fine, but never developed the iconic pods. I dug up some of the radish roots, and discovered that it looked like the daddy radish was possibly the daikon radishes that had been growing near the momma rat tail radish. While the radishes were tasty, I didn’t get the rat tail seed pods to eat like I wanted.

OP radish cross from rat tail mom and possibly a daikon dad. Technically these were a “hybrid.”


Those OP plants that crossed with unalike cultivars produce plants that are called hybrids. This can be a good thing if you need some disease resistance or faster growth, but not so good when you want a tasty soft skinned zucchini and you get a zucchini with the rind of a pumpkin.

F1 Hybrid

This term is applied to the first generation hybrid. F1 for first. (F2 would be second generation.)  F1 hybrids occur anytime – but for the seed sale business it is a very specific term.

F1 is used when a breeder selects two pure lines (plants that produce identical offspring when self-pollinated) and cross-pollinates them to produce a seed that combines desirable characteristics or “traits” from both parents. Common traits breeders work to increase in hybrids can include, disease resistance, uniformity, earliness, high nutrition, or a specific color.


F1 hybrid seed is often more expensive than OP or non-hybrid seed, due to production methods. It is difficult to maintain the separate two pure parent lines, and then they must be cross pollinated so that F1 seed can be produced each year. Note that the cross-pollinating is often done by hand!

Seeds can be saved and planted from F1 hybrids that are allowed to OP but plants grown from that seed “will not come true” – in other words, they may lack the desirable characteristics of the parents, which were crossed specifically to incorporate them.



Heirlooms are generally defined as open pollinated (OP) varieties that have resulted from natural selection rather than a controlled plant breeding and hybridization process.

Sometimes 50 years is used as an arbitrary age marker to define what constitutes an heirloom variety. Meanwhile, others classify any cultivated variety as an “heirloom” if it was developed prior to the 1950’s. Why this date? Starting in the 1960s, plant breeders began producing and selling many of the modern hybrid varieties.

Like any other open-pollinated variety, seed saved from an heirloom produces plants with the same characteristics as the parent plant. Examples of popular home garden heirlooms offered by many packet seed companies include Clemson Spineless okra, Cucumber Straight 8, Carrot Imperator, and Tender Pod beans.

The romantic view of heirlooms is that they are varieties that have been passed down through generations of gardeners. Though this was certainly true in the past, it is often not the case in our modern world. Commercial seed companies now produce tons (tons!) of seeds of many celebrated heirloom varieties. They sell this seed to seed packet companies. Those seed package companies put their own labels on them and offer them to home gardeners.

Organic, GMO and GE are topics for a later post.

Here I am at the HGSA 2017 Summer Conference and Seed Trials. We helped sample possible new varieties and evaluate them for flavor.

Authors Note

This article is a blend of my discussion published in my book Southwest Fruit & Vegetable Gardening, Revised Edition, an article I wrote for a (now defunct) newspaper in Idaho in 1995, and an article written by and published on the Home Garden Seed Association (HGSA) website. HGSA is a group of seed producers and seed packet retailers committed to supporting home gardening success, specifically through the use of seeds.  The cover banner image is courtesy of them.

Gifting Season Approaches – Give the Gift of Growing

soule-books-buyOne reviewer said:

“A great reference book is key to successful gardening in the region where you live. Arizona, Nevada & New Mexico Month-by-Month Gardening takes the guesswork out of gardening for anyone residing in the Southwest. With this book, you’ll know what to do each month to enjoy a thriving garden all year, from January to December. Chronologically organized, this guide is full of critical gardening when-to and how-to advice, along with illustrated step-by-step instructions.

The book’s author is Jacqueline Soule, a Tucson-based gardening expert. She knows this arid region inside and out, and she’s written several articles and books packed with her gardening advice. Arizona, Nevada & New Mexico Month-by-Month Gardening showcases Soule’s expertise in one easy-to-read guide.”

This book (and others) are available on my book selling site.  Buy the book there, and the Horticulture Therapy non-profit Tierra del Sol Institute will get a few pennies – at no extra cost to you.


Or maybe a class?  Make some lotion for winter dry skin.

On advice of a business manager – I was told to more actively sell my “products.”   I responded, “Start blowing my own horn more?!  I’m a gardener and a writer, not a sales agent!” but here goes:

As well as writing about plants, I offer classes online and in person.

Like my Making Herbal Lotion Class.

Then there is the fun and informative Membership site the Gardening With Soule Membership Club. There are many wonderful features to the Club site – in-depth detail on topics (more than mere blog posts) – specific plant profiles – care videos – monthly live Q & A sessions, and much more.

Why do I do all this writing and teaching?

So that you will succeed with your gardening goals, and enjoy gardening here as much as I do!

Thanks for reading,



© Article copyright Dr. Jacqueline A. Soule. All rights reserved. You must ask permission to republish an entire blog post or article. Okay to use a short excerpt but you must give proper credit. You must include a link to the this original post on my site. No stealing photos.


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