And if you went looking for answers, you probably found three of them repeated everywhere you turned: sprinkle in some crushed eggshells, spray on some calcium, add a scoop of Epsom salt. All three of those are extremely common advice. Two of them do close to nothing. And one of them can genuinely make the problem worse.
That problem? Blossom end rot.
Today on Just Grow Something we're covering what blossom end rot really is at the cellular level, the conditions that trigger it in your garden, why the most popular home remedies for it are built on a total misunderstanding of the problem, and what the research consistently recommends instead.
Let's dig in.
University Extension and Research-Based Resources
Utah State University Extension — Blossom End Rot (IPM Fact Sheet) https://extension.usu.edu/planthealth/ipm/notes_ag/veg-blossom-end-rot
Purdue Extension — Blossom End Rot of Tomato Fruit (BP-13-W) https://www.extension.purdue.edu/extmedia/bp/bp-13-w.html
University of Maryland Extension — Blossom End Rot on Vegetables https://extension.umd.edu/resource/blossom-end-rot-vegetables
Alabama Cooperative Extension System — Blossom-End Rot in Tomatoes: Causes and Prevention (ANR-1059) https://www.aces.edu/blog/topics/lawn-garden/blossom-end-rot-in-tomatoes-causes-and-prevention/
University of Massachusetts Amherst, Center for Agriculture, Food, and the Environment — Solanaceous: Blossom End Rot https://ag.umass.edu/vegetable/fact-sheets/solanaceous-blossom-end-rot
Oregon State University Extension — Blossom-End Rot of Tomatoes (FS-139) https://extension.oregonstate.edu/catalog/fs-139-blossom-end-rot-tomatoes
University of Wisconsin Horticulture Extension — Blossom End Rot https://hort.extension.wisc.edu/articles/blossom-end-rot/
University of California Cooperative Extension, UC ANR "The Real Dirt" — Fighting Blossom End Rot https://ucanr.edu/blog/real-dirt/article/fighting-blossom-end-rot
University of Connecticut Extension — Put an End to Blossom-End Rot: Water and Nutrient Management is Key https://homegarden.cahnr.uconn.edu/2025/06/15/blossom-end-rot/
Clemson Cooperative Extension HGIC — Gardening Myths: Fix Blossom End Rot with Calcium Sprays https://hgic.clemson.edu/gardening-myths-fix-blossom-end-rot-with-calcium-sprays/
North Dakota State University Extension — The Epsom Salt Myth https://www.ndsu.edu/agriculture/extension/extension-topics/gardening-and-horticulture/vegetables/epsom-salt-myth
University of Minnesota Extension — Do Common Soil Health "Home Remedies" Work? (Coffee Grounds, Eggshells, Epsom Salts) https://extension.umn.edu/manage-soil-nutrients/coffee-grounds-eggshells-epsom-salts
Peer-Reviewed Research
Topcu, Y., Nambeesan, S. U., & van der Knaap, E. (2022). Blossom-end rot: a century-old problem in tomato (Solanum lycopersicum L.) and other vegetables. Molecular Horticulture, 2, 1. https://doi.org/10.1186/s43897-021-00022-9
Just Grow Something: https://justgrowsomething.com
Gardening Courses: https://justgrowsomething.com/courses
Just Grow Something Merch and Downloads: https://justgrowsomething.com/shop
Just Grow Something Gardening Friends Facebook Group: https://www.facebook.com/share/g/18YgHveF5P/
Check out how you can become a patron on Patreon: https://www.patreon.com/JustGrowSomething
Feed my coffee habit: https://buymeacoffee.com/justgrowsomething
Amazon storefront: https://www.amazon.com/shop/justgrowsomething
Get 10% off and FREE shipping on my favorite raised planters at Planter Box Direct using code JUSTGROW10: https://planterboxdirect.com/?ref=593