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.
Get your free gift, great coffee, and support the show at https://larryscoffee.com/justgrow
Tell me about your garden goals and challenges, get a quote, and get on my calendar: https://JustGrowSomething.com/gardenconsulting
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