Just Grow Something | Evidence-Based Home Gardening

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

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Fall gardening doesn't start in September. For the crops that take a long time to produce, your broccoli, your cauliflower, your cabbage, your Brussels sprouts, it starts right now in late June and early July. And if you've never had a productive fall brassica bed, it's almost certainly because you started too late and it took me a lot of years to master this.

This episode is about fall gardening planning, and specifically about the crops that require you to be thinking ahead right now, in late June and into July, when literally nothing about summer conditions suggest that fall is coming.

We’re talking about the timing, why it matters, how to calculate it for your specific first frost date, and exactly what to do if you're sitting here thinking you may have already missed the window — because you might not have, but we need to move quickly.

Let’s dig in.

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Resources:

How to Calculate Your Fall Brassica Dates

Step 1: Find your average first frost date (garden.org/apps/frost-dates or your local extension service)

Step 2: Take days to maturity for your chosen variety

Step 3: Add 10–14 days for the short-day factor

Step 4: Count backward from first frost — that is your transplant-out deadline

Step 5: Count back another 4–6 weeks — that is your seed-starting deadline

MU Extension — Vegetable Planting Calendar (G6201): Variety-specific fall planting dates for Missouri's three planting regions. https://extension.missouri.edu/publications/g6201
UMN Extension — Growing Broccoli: Seed-starting timing (early to late July for fall crop), variety selection, and fall head quality. https://extension.umn.edu/vegetables/growing-broccoli

UMN Extension — Growing Broccoli: Seed-starting timing (early to late July for fall crop), variety selection, and fall head quality. https://extension.umn.edu/vegetables/growing-broccoli

UMN Extension — Growing Brussels Sprouts: Start seeds in June indoors or direct, water deeply once weekly, harvest through fall frosts. https://extension.umn.edu/vegetables/growing-brussels-sprouts

UMN Extension — Growing Cauliflower: Start seeds in July for fall crop; cool temperatures essential for quality curd formation. https://extension.umn.edu/vegetables/growing-cauliflower

UMN Extension — Growing Cabbage: For fall crop, plant seed directly in garden in early July; cabbage takes 60–100 days. https://extension.umn.edu/vegetables/growing-cabbage

UMD Extension — Planting Dates for Vegetable Crops (Transplant Timing): Short-day factor methodology for fall transplant timing. https://extension.umd.edu/sites/extension.umd.edu/files/2021-03/PlantingDatesforVegetableCropsinMaryland.pdf

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It’s June, your tomatoes are climbing, your corn is waist-high, and the internet is full of fertilizing advice—most of it missing the most important variable: timing. In this episode, we dig into what your vegetables need right now at mid-season, why nitrogen timing is the thing most gardeners get wrong, how fruiting crops and leafy crops have completely different needs, and when fertilizing can actually hurt instead of help. We’ll cover how to read your plants for deficiency signs, how to side-dress correctly, and why the most common mid-season mistake isn’t under-fertilizing—it’s fertilizing at the wrong time with the wrong form. Grounded in university extension research and my own experience farming through Missouri summers, this one will give you a clear, crop-by-crop picture of what to do right now. Let’s dig in.

Crop-by-Crop Quick Reference: Mid-Season Nitrogen Timing

LEAFY CROPS (lettuce, kale, chard, spinach, collards, arugula, basil)

When to side-dress: 3–4 weeks after transplanting or when 2–3 inches tall; repeat every 4–6 weeks for heavy-harvesting crops

Goal: steady nitrogen supply throughout season

Note: don’t exceed recommended rates—excess nitrogen increases pest/disease vulnerability

COLE CROPS (broccoli, cabbage, cauliflower)

When to side-dress: approximately 30 days after transplanting, during active vegetative growth

Hold off once head formation begins

TOMATOES

When to side-dress: when first fruits are approximately one-third grown (golf ball size)

DO NOT apply nitrogen at transplant or during early fruit set—drives vegetative growth at expense of fruit

Second application: 2 weeks after first ripe fruit; third: 4 weeks later

Rate: 0.5 lb actual nitrogen per 100 feet of row per application

PEPPERS

When to side-dress: early vegetative growth before fruit set

Pull back after fruit is setting

SWEET CORN

When to side-dress: when plants are approximately one-third grown (knee-high)

Apply alongside rows, not into the whorl of leaves

May benefit from a second application before tasseling

CUCUMBERS / SQUASH / MELONS

When to side-dress: after vines are well-established and fruit is setting regularly

Not during early flowering window

For squash with blossom drop only: do not add nitrogen—address pollination instead

BEANS / PEAS (inoculated)

Mid-season nitrogen side-dressing generally not needed if seeds were inoculated

Extra nitrogen causes excessive leaf growth and reduced pod set

If not inoculated: apply light nitrogen early in vegetative growth only

Side-Dressing How-To

Move mulch aside before applying; replace afterward

Keep granular fertilizer 4–6 inches from plant stems to prevent burn

Work granular into top 1–2 inches of soil

Water in after application—nitrogen moves into the root zone with moisture

Organic options: blood meal or alfalfa pellets (work in lightly; slower to show results); fish emulsion (liquid, faster uptake, more frequent application needed)

Signs of Nutrient Deficiency

Nitrogen: yellowing starting on oldest, lowest leaves; stunted or stalled growth

Phosphorus: stunted growth; reddish-purple tint in leaf tissue (often triggered by cold soil, not low soil P)

Potassium: browning at leaf edges, starting with older leaves

Note: many of these symptoms overlap with stress from crowding, insufficient sun, compaction, waterlogged roots, or nematode damage—rule those out first

Common Myths Addressed

Myth: More fertilizer = more production. The research is clear: overapplied nitrogen causes excess vegetative growth at the expense of fruit, increases pest and disease vulnerability, and leaches into groundwater without benefiting plants.

Myth: If plants look off, they need fertilizer. Nutrient deficiency symptoms look almost identical to symptoms of watering problems, compaction, pH issues, root damage, and pest pressure. Identify the actual cause before applying anything.

Myth: Tomatoes need nitrogen all season long. Timing matters. Nitrogen during the early fruit-set window drives vegetative growth and reduces yields. Wait until fruit is sizing up before side-dressing.

Myth: Beans and peas are heavy feeders like corn. Inoculated legumes fix their own nitrogen from the air. Additional nitrogen pushes leaf growth at the expense of pods.

Resources

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Soil test kit: https://amzn.to/4vqYMk1

University Extension Publications

University of Minnesota Extension – Quick Guide to Fertilizing Plants

Oregon State University Extension – Feed Your Vegetable Garden Midseason to Boost Growth and Yields

Oregon State University Extension – Vegetable Gardening in Oregon (EC 871)

University of Maryland Extension – Fertilizing Vegetable Gardens

University of Missouri Extension – Growing Home Garden Tomatoes (G6461)

University of Missouri Extension – Vegetable Gardening (MG 5) – Table 1: Recommended Nitrogen Side-Dressings

University of Missouri Extension IPM – Side-Dressing: Mid-Season Boost for Hungry Plants

Virginia Tech Extension – Fertilizing the Vegetable Garden (426-323)

Mississippi State University Extension – Fertilizing Vegetable Gardens

University of Nevada, Reno Extension – Fertilizing Your Vegetable Garden

 
Connect

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Every June, one of the most common questions that floods gardening groups, emails, and extension offices is some version of: “My tomato leaves are turning brown — do I have blight?” The confusion is completely understandable, because there are two diseases that get lumped under that word — and they are caused by completely different organisms, show up in different ways, and require completely different responses. Treating late blight like early blight — or vice versa — can mean the difference between saving your plants and losing your entire harvest.

In this episode, horticulturist and market farmer Karin Velez breaks both diseases down in plain language: what they look like, where they show up on the plant, what conditions favor them, how fast they move, what happens if you ignore them, and exactly what to do when you find either one. Whether you’re seeing spots on your lowest leaves or a whole section of your garden that looks like it got hit by frost overnight, this episode will help you figure out what you’re looking at — and what to do next.

Let’s dig in.

References and Resources

Captain Jack’s Copper Fungicide - https://amzn.to/43DKqAn

Penn State Extension — Tomato Diseases and Disorders in the Home Garden:

https://extension.psu.edu/tomato-diseases-and-disorders-in-the-home-garden

Penn State Extension — Scouting and Identifying Tomato Diseases:

https://extension.psu.edu/scouting-and-identifying-tomato-diseases

Penn State Extension — Tomato-Potato Late Blight in the Home Garden:

https://extension.psu.edu/tomato-potato-late-blight-in-the-home-garden

University of Georgia Extension — Common Tomato Diseases in Georgia (Bulletin B1285):

https://extension.uga.edu/publications/detail.html?number=B1285&title=common-tomato-diseases-in-georgia

UGA Extension, Madison County — Tomato Troubles:

https://site.extension.uga.edu/madison/2021/08/tomato-troubles/

University of Minnesota Extension — Late Blight of Tomato and Potato:

https://extension.umn.edu/disease-management/late-blight

Michigan State University Extension — Organic Management of Early Blight on Tomato (Hausbeck Lab):

https://www.canr.msu.edu/hausbeck/Uploads/PDF/FS_Organic-Management-of-Early-Blight-on-Tomato.pdf

UC ANR / UC IPM — Late Blight of Tomato (Phytophthora infestans):

https://ipm.ucanr.edu/agriculture/tomato/late-blight/

Pacific Northwest Pest Management Handbooks — Tomato Late Blight:

https://pnwhandbooks.org/plantdisease/host-disease/tomato-solanum-lycopersicum-late-blight

Cornell University — Disease-Resistant Vegetable Varieties (late blight resistance):

https://www.vegetables.cornell.edu/pest-management/disease-factsheets/disease-resistant-vegetable-varieties/

Midwest Vegetable Production Guide — current fungicide recommendations for late blight (referenced by Penn State and UMN Extension): https://mwveguide.org/

USAblight.org — national real-time late blight tracking and outbreak alerts (when it’s working?): http://usablight.org/

Quick-Reference: Early Blight vs. Late Blight at a Glance

Pathogen type | Early Blight: true fungus (Alternaria solani)  |  Late Blight: water mold / oomycete (Phytophthora infestans)

Ideal temperature | Early Blight: 68–77°F (warm)  |  Late Blight: 60–78°F (cool to mild)

Where it starts | Early Blight: oldest/lowest leaves first  |  Late Blight: anywhere on the plant, no pattern

Lesion appearance | Early Blight: dark bullseye with concentric rings, yellow halo  |  Late Blight: large irregular dark oily blotch, gray-green edge, no rings

Underside of leaf | Early Blight: dark spores in lesion center  |  Late Blight: white downy/powdery growth at lesion margins in humidity

Speed | Early Blight: slow and progressive, weeks to months  |  Late Blight: explosive, can kill plant in ~14 days

Fruit symptoms | Early Blight: sunken dark spot at stem attachment  |  Late Blight: firm dark brown spot starting at fruit shoulders

Overwinters as | Early Blight: debris/soil/seeds in warm climates  |  Late Blight: infected potato tubers, volunteer plants

Fungicide type | Early Blight: copper, sulfur, standard fungicides  |  Late Blight: oomycete-specific only — NOT standard fungicides

Response urgency | Early Blight: act promptly, manageable with cultural controls  |  Late Blight: emergency response, remove immediately, notify extension and neighbors

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