Seed Saving: Harvesting, Drying and Storing for Next Season - Ep. 322

Every fall somebody asks me if they can save the seeds from that amazing tomato or melon they just ate, and the answer is "maybe." Whether a saved seed grows into the plant you loved gets decided twice. The first time is months earlier, when the flower was pollinated, and the second is after harvest, when the seed either stays in the right conditions or doesn't.

In this episode we're covering both. We'll talk about hybrids versus open-pollinated and heirloom varieties, which crops are easiest for beginners, why your zucchini and your pumpkin can cross but your cucumber and your cantaloupe can't, and why peppers cross more often than most people think.

Then we'll get into harvesting and cleaning seeds, including what tomato seed fermentation does and doesn't do for seedborne disease, how to dry seeds without cooking them, the simple temperature-plus-humidity rule for storage, and why seed longevity charts don't agree with each other.

Let’s dig in.

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Six Steps for Saving Seeds From Your Garden: https://justgrowsomethingpodcast.com/blog/six-steps-for-saving-seeds-from-your-garden

References and Resources

Choosing Crops, Pollination, and Isolation

• University of Minnesota Extension — Saving Vegetable Seeds (open-pollinated vs. hybrid, cross-pollination, harvesting, storage, bacterial canker and seed treatments): https://extension.umn.edu/planting-and-growing-guides/saving-vegetable-seeds
• University of Illinois Extension — How to Save Seeds (terms, isolation methods, isolation distance table, wet and dry harvesting): https://extension.illinois.edu/sites/default/files/how_to_save_seeds_062021.pdf
• University of Maryland Extension — Seed Saving 101: Vegetables (three levels of seed saving, tomato and potato-leaf isolation, pepper species crossing, squash after-ripening, storage rule of thumb): https://extension.umd.edu/sites/extension.umd.edu/files/2021-02/Seed%20Saving%20Veggies%20Resources.pdf
• UC Agriculture and Natural Resources, Orange County 4-H — Saving Seed from the Three Sisters and Tomatoes (population sizes for home gardens): https://oc4h.ucanr.edu/sites/default/files/2016-09/248080.pdf
• NC State Extension, Onslow County — Saving Your Own Seed (hot and sweet pepper crossing): https://onslow.ces.ncsu.edu/2023/01/saving-your-own-seed/
• Barchenger, D.W., et al. (2025). Producing High Quality Pepper Seed. World Vegetable Center, Publication No. 25-1099 (pepper outcrossing rates, bee visitation, seed moisture): https://worldveg.tind.io/record/76153/files/25-1099_Producing%20high%20quality%20pepper%20seed.pdf

Harvesting, Cleaning, and Seedborne Disease

• Oregon State University Extension — Collecting and Storing Seeds From Your Garden (crop-by-crop harvesting, hand-pollinating squash, bean weevils, longevity groups, germination testing): https://extension.oregonstate.edu/gardening/techniques/collecting-storing-seeds-your-garden
• Pradhanang, P.M., & Collier, G. (2009). How effective is hydrochloric acid treatment to control Clavibacter michiganensis michiganensis contamination in tomato seed? Acta Horticulturae 808: 81–86 (overnight fermentation vs. washing): https://doi.org/10.17660/ActaHortic.2009.808.10

Drying, Storage, and Longevity

• Colorado State University Extension — Storing Vegetable and Flower Seeds, Fact Sheet 7.221 (drying temperatures, seed moisture, humidity, hard seed, federal minimum germination and longevity table): https://extension.colostate.edu/resource/storing-vegetable-and-flower-seeds/
• University of Delaware Cooperative Extension, Weekly Crop Update — Storing Vegetable Seed (temperature-plus-humidity rule, storage life halving rules, freezing seed): https://sites.udel.edu/weeklycropupdate/?p=2967

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