Just Grow Something | Evidence-Based Home Gardening

If you've listened to this show for any length of time, you've heard me point to University Extension again and again as my go-to source. But I've never actually explained why.

In this episode, we're pulling back the curtain on the Cooperative Extension System: where it came from, starting with farmers comparing notes in the early 1800s, through the Morrill Act's creation of land-grant universities in 1862, the Hatch Act's 1887 research mandate, and the 1914 Smith-Lever Act that built the nationwide Extension system we know today.

We'll also trace the Master Gardener program from its 1972 origins in Washington State and we'll get honest about reliability: how peer review works (and where it doesn't), how to evaluate a publication for yourself, and why regional, research-based information matters more than ever in an age of viral gardening myths.

This one's less about your garden bed and more about why you can trust what I tell you to put in it. Let’s dig in!

Episode References

https://LarrysCoffee.com/JustGrow – Free Gift with order from this link only!

Battling Blossom End Rot the Right Way - Ep. 309

Raised Bed Gardening with Gardener Scott - Ep. 268

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Resources

Rutgers Cooperative Extension — The 1914 Smith-Lever Act: https://extension.rutgers.edu/history/smith-lever

OSU Extension — A Brief History of Extension: https://extension.osu.edu/about/mission-vision-values/osu-extension-brief-history

USDA NIFA — History: https://www.nifa.usda.gov/about-nifa/who-we-are/history

USDA NIFA — Cooperative Extension History: https://www.nifa.usda.gov/about-nifa/what-we-do/extension/cooperative-extension-history

USDA NIFA — What We Do: Extension: https://www.nifa.usda.gov/about-nifa/what-we-do/extension

gov CRS — The Agricultural Cooperative Extension System: An Overview: https://www.congress.gov/crs-product/R48071

gov CRS — The U.S. Land-Grant University System: https://www.congress.gov/crs-product/R45897

APLU — Land-Grant University FAQ: https://www.aplu.org/about-us/history-of-aplu/what-is-a-land-grant-university/

Land-Grant Impacts — Extension (current office count): https://landgrantimpacts.org/extension/

Garden Professors — Not All Extension Publications Are Created Equal: https://gardenprofessors.com/not-all-extension-publications-are-created-equal/

OSU Extension — Peer Review Guidelines: https://extension.oregonstate.edu/peer-review-guidelines

University of Illinois Extension — Peer Reviewed Publications: https://extension.illinois.edu/global/peer-reviewed-publications

Clemson News — Land-Grant Press Publications: https://news.clemson.edu/land-grant-press-publications-provide-vital-knowledge-from-clemson-cooperative-extension-program-areas/

Washington State University — History of the Master Gardener Program: https://mastergardener.wsu.edu/who-we-are/history/history-of-the-master-gardener-program/

WSU CAHNRS News — Seeds of a Movement: 50 Years Ago: https://news.cahnrs.wsu.edu/article/seeds-of-a-movement-50-years-ago-master-gardeners-began-with-wsu-trained-volunteers/

University of Missouri Extension — History of Extension: https://extension.missouri.edu/about-us/history-of-extension

Master Gardeners of Greene County — History (Missouri program): https://mggreene.org/history/

University of Missouri Extension — Extension Master Gardener Program: https://extension.missouri.edu/programs/extension-master-gardener

OSU Extension — Experts Debunk 10 Common Gardening Myths: https://extension.oregonstate.edu/news/osu-extension-experts-debunk-10-common-gardening-myths

University of Arkansas ScholarWorks — Social Media Misinformation Among Extension Educators (dissertation): https://scholarworks.uark.edu/etd/5861/

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For most of the last century, gardeners were taught to cultivate their soil after every rain to conserve moisture, to think of plant roots as lone competitors, and to treat "plant communication" as science fiction. All of that was built on the best evidence available at the time, and all of it has been revised, in some cases more than once, as better tools let researchers see what earlier generations simply could not. In this episode, we walk through four real case studies of plant science changing its mind. Along the way, we talk about how the scientific method works, why one of my favorite phrases, "we don't know what we don't know," is not a discouraging idea but an exciting one, and what all of this means for the choices you make in your own garden each season, now and into the future.

Let’s dig in!

References and Resources:

Chalker-Scott, L., and C.H. Daniels. (2016). "Scientific Literacy for the Citizen Scientist." WSU Extension Manual EM100E. https://wpcdn.web.wsu.edu/extension/uploads/sites/30/2024/07/Scientific-Literacy-for-the-Citizen-Scientist.pdf

Chalker-Scott, L. (2021, revised). "Dust Mulch Efficacy in Gardens and Landscapes." WSU Extension Fact Sheet FS167E. https://wpcdn.web.wsu.edu/wp-ecommerce/uploads/sites/2/product-3540-sku-FS167E.pdf

Chalker-Scott, L. (2017). "A Gardener's Primer to Mycorrhizae: Understanding How They Work and Learning How to Protect Them." WSU Extension Fact Sheet FS269E. https://wpcdn.web.wsu.edu/wp-ecommerce/uploads/sites/2/product-3286-sku-FS269E.pdf

Chalker-Scott, L. (2023). "Gardening with Companion Plants." WSU Extension Publication EM128E. https://pubs.extension.wsu.edu/product/gardening-with-companion-plants-home-garden-series/

Oklahoma State University Extension. "Mycorrhizal Fungi." Fact Sheet. https://extension.okstate.edu/fact-sheets/mycorrhizal-fungi

Pacific Horticulture Society. "Mycorrhizal Fungi, Nature's Key to Plant Survival and Success." https://pacifichorticulture.org/articles/mycorrhizal-fungi-natures-key-to-plant-survival-and-success/

Cao, D., Chabikwa, T., Barbier, F., Dun, E.A., Fichtner, F., Dong, L., Kerr, S.C., & Beveridge, C.A. (2023). "Auxin-independent effects of apical dominance induce changes in phytohormones correlated with bud outgrowth." Plant Physiology, 192(2), 1420–1434. https://doi.org/10.1093/plphys/kiad034

Mason, M.G., Ross, J.J., Babst, B.A., Wienclaw, B.N., & Beveridge, C.A. (2014). "Sugar demand, not auxin, is the initial regulator of apical dominance." Proceedings of the National Academy of Sciences, 111(16), 6092–6097. https://www.pnas.org/doi/10.1073/pnas.1322045111

Barbier, F.F., Dun, E.A., & Beveridge, C.A. (2017). "A Growing Stem Inhibits Bud Outgrowth — The Overlooked Theory of Apical Dominance." Frontiers in Plant Science, 8:1874. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5671643/

"Lessons from a century of apical dominance research." (2023). Journal of Experimental Botany. https://pmc.ncbi.nlm.nih.gov/articles/PMC10400159/

Simard, S.W., Perry, D.A., Jones, M.D., Myrold, D.D., Durall, D.M., & Molina, R. (1997). "Net transfer of carbon between ectomycorrhizal tree species in the field." Nature, 388, 579–582. https://www.nature.com/articles/41557

"Belowground carbon transfer across mycorrhizal networks among trees: Facts, not fantasy." (2023). Review discussing the scope and limits of current evidence for mycorrhizal carbon transfer. https://pmc.ncbi.nlm.nih.gov/articles/PMC10751480/

Baldwin, I.T., & Schultz, J.C. (1983). "Rapid Changes in Tree Leaf Chemistry Induced by Damage: Evidence for Communication Between Plants." Science, 221(4607), 277–279. https://www.science.org/doi/10.1126/science.221.4607.277

Heil, M. (2014). "Herbivore-induced plant volatiles: targets, perception and unanswered questions." New Phytologist, 204(2), 297–306. https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.12977

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Your garden is at its busiest in July, and so is the wear and tear on your soil. In this episode we get past the fertilizer conversation and into whether your soil is still functioning at all — how traffic, pounding rain, heat, and heavy-feeding crops degrade soil mid-season, the physical, chemical, and biological warning signs to look for right now, and tests you can run this week to sort the problems. Plus, how to use a mid-season open bed as a soil-building opportunity.

Let's dig in!

REFERENCES & RESOURCES

University of Delaware Cooperative Extension — "Combating Soil Compaction" — https://www.udel.edu/academics/colleges/canr/cooperative-extension/fact-sheets/combating-soil-compaction/

University of Minnesota Extension — "Backyard science: Is your soil healthy?" (slake test, infiltration test, earthworm counts) — https://extension.umn.edu/yard-and-garden-news/backyard-science-your-soil-healthy

Cornell Soil Health Laboratory — Individual soil analyses, including wet aggregate stability — https://soilhealthlab.cals.cornell.edu/testing-services/individual-soil-analyses/

Purdue University Vegetable Crops Hotline — "Nitrogen Loss from Wet Soils" — https://vegcropshotline.org/article/nitrogen-loss-from-wet-soils/

UF/IFAS Extension — CIR 1092/SS117, "Soil and Container Media Electrical Conductivity Interpretations" — https://ask.ifas.ufl.edu/publication/SS117

Texas A&M AgriLife, Aggie Horticulture — "Salt Injury" (Cucurbit Problem Solver) — https://aggie-horticulture.tamu.edu/vegetable/problem-solvers/cucurbit-problem-solver/leaf-disorders/salt-injury/

Purdue University Vegetable Crops Hotline — "Summer Cover Crops for Improved Soil Health and Weed Management" — https://vegcropshotline.org/article/summer-cover-crops-for-improved-soil-health-and-weed-management/

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If you've grown tomatoes or peppers for more than one season, you more than likely know the feeling been waiting that first tomato to ripen, finally see it’s blushing red, and you flip it over to find a sunken, leathery patch covering half the bottom of the fruit. 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

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It's two o'clock on a July afternoon. You walk out to check the garden, and your squash leaves are drooping so low they're nearly touching the mulch. Your tomato plants look like they've given up on the whole season. If your first thought, every single time, is “I need to water right now,” hold on a second before you grab that hose. Because that dramatic afternoon collapse you're looking at likely has absolutely nothing to do with how much water is in your soil.

So today on Just Grow Something we're covering three things: what's actually happening inside a plant's cells when the temperature spikes, the specific ways to tell heat stress wilting apart from drought stress wilting, and what heat stress does beyond the leaves, because your tomatoes and peppers and squash can look perfectly fine and still be failing to set fruit, and that's a heat problem too.

Let's dig in.

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References and Resources:

Graci, S., & Barone, A. (2024). Tomato plant response to heat stress: a focus on candidate genes for yield-related traits. Frontiers in Plant Science, 14, 1245661. https://doi.org/10.3389/fpls.2023.1245661

Sellami, D., & Kooli, S. (2025). Physiological and growth responses of tomato plants to heat stress. Discover Plants. https://doi.org/10.1007/s44372-025-00462-3

University of Maryland Extension — Drought and Excessive Heat Stress  https://extension.umd.edu/resource/drought-and-excessive-heat-stress

University of Maryland Extension — Pollination of Vegetable Crops in a Changing Climate https://extension.umd.edu/resource/pollination-vegetable-crops-changing-climate

NC State Cooperative Extension, Beaufort County — What "Wilting" Really Means: Heat Stress vs. Water Needs https://beaufort.ces.ncsu.edu/news/what-wilting-really-means-heat-stress-vs-water-needs/

Oregon State University Extension — Heat Wave in the Garden: How to Identify and Prevent Heat Stress in Plants https://extension.oregonstate.edu/catalog/em-9556-heat-wave-garden-how-identify-prevent-heat-stress-plants

Oregon State University Extension — Why Vegetables Drop Blossoms https://extension.oregonstate.edu/news/why-vegetables-drop-blossoms

Oregon State University Extension — Mother Nature May Need Help to Pollinate Squash and Cucumbers https://extension.oregonstate.edu/news/mother-nature-may-need-help-pollinate-squash-cucumbers

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

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