How to Identify a Real Heirloom Tomato

The word "heirloom" has been overused in marketing. Every seed catalog now claims heirlooms. But a real heirloom tomato is something specific: an open-pollinated variety that's been grown for generations, usually by a family or community, producing seeds that grow true. Not every old tomato qualifies. And knowing the difference matters if you want to save seeds.

The Genetics: Open-Pollinated vs. Hybrid

Open-pollinated (OP) tomatoes pollinate via wind or insects. Flowers are self-fertile. If you grow an OP tomato and let it self-pollinate, seeds produce plants that are genetically identical (or nearly so) to the parent. This is why heirlooms work: save seeds, grow identical plants next year.

Hybrid tomatoes are first-generation crosses between two inbred lines. F1 hybrids are vigorous, uniform, and often disease-resistant. But if you save seeds from a hybrid, the next generation segregates—you'll get a mix of traits, not the original plant. This is intentional. Seed companies want you to buy new seeds every year.

Heirlooms are OP. Hybrids are F1. Know which you're buying.

Reading the Label: How to Spot OP Designations

Seed catalogs use abbreviations:

"OP" or "Open-Pollinated" = This is the real deal. Save seeds if you like.

"F1 Hybrid" = Don't save seeds. Next generation won't be the same.

"Heirloom" = Usually OP, but check the fine print. Some catalogs use "heirloom" loosely.

"Determinate" or "Indeterminate" = Growth habit, not genetics. Heirlooms can be either.

Look for the "OP" designation explicitly. If a seed packet says "heirloom" but doesn't say "open-pollinated," ask the seller.

Famous Heirloom Tomatoes (All OP)

Brandywine — large, pink-red, exceptional flavor. Grows 70–85 days. Worth the wait.

Cherokee Purple — dark red with green shoulders. Complex flavor. Can be disease-prone but oh, the taste.

Mortgage Lifter — named because it supposedly sold for enough to pay a mortgage. Large, productive, reliable.

San Marzano — Italian paste tomato. Dense, low-seed, perfect for sauce. Determinate.

Striped varieties (Tigerella, Green Zebra) — true heirlooms with distinctive coloring and flavor.

Why Seed-Saving Works (For OP, Not Hybrids)

Seed-saving is simple:

1. Let a ripe tomato fully mature on the plant.

2. Cut it open, scoop seeds and gel into a jar.

3. Let it ferment for 2–3 days (the gel has natural enzymes that help).

4. Rinse seeds thoroughly, dry on paper or cloth for 3–4 weeks.

5. Store in cool, dry conditions. Next spring, plant.

This works for OP tomatoes because genetic traits are stable. You get Brandywine seeds that grow Brandywine tomatoes. Try this with an F1 hybrid and you'll get a mess of random plants.

Seed-saving is legal and practical for home gardeners growing OP varieties. It's a way to maintain genetic diversity and reduce dependency on seed catalogs.

Utah State University Extension—Seed Saving for Tomatoes — Dr. Dan Drost (2023)

Does It Matter for Utah Gardeners?

Maybe. If you want to save seeds and grow the same tomato next year, buy OP. If you just want great tomatoes and don't care about seed-saving, hybrids are often more disease-resistant and reliable in our climate.

We recommend: try both. Grow one heirloom (save seeds, learn the process). Grow one hybrid (enjoy the reliability). Compare notes next season.

Heirloom tomatoes aren't better because they're old. They're better because they're genetically stable and they carry flavor that's been optimized by generations.

Learn Seed-Saving Techniques