Magnesium + Sulfur — Instant Correction

Best Epsom Salt for Plants (0-0-0 + 9.8% Mg + 13% S): Water-Soluble Magnesium & Sulfur for Chlorophyll, Flavor & Green-Up Buy on Old Cobblers Farm

Updated April 2026 By the Old Cobblers Farm Team

Old Cobblers Farm™ Wicked Organics Magnesium Sulfate

by Wicked Organics — Littleton, NH

0-0-0
N-P-K Ratio
"The fastest magnesium correction available. 9.8% magnesium and 13% sulfur dissolve instantly in water for immediate uptake through leaves or roots. Corrects interveinal chlorosis, boosts chlorophyll production, and enhances flavor compounds in tomatoes, peppers, and herbs."
9.8%
Magnesium
13%
Sulfur
500 ft²
Soil Coverage / bag
4 Sizes
5, 10, 15, 20 lbs
🧪

9.8% Magnesium + 13% Sulfur

Two critical secondary nutrients in one water-soluble crystal. Magnesium drives chlorophyll production. Sulfur supports protein synthesis and flavor compound development.

💧

Instantly Water Soluble

Dissolves completely in water for immediate availability. Foliar spray delivers magnesium directly through leaf tissue for the fastest possible deficiency correction.

🍅

Tomato & Pepper Essential

Tomatoes and peppers are heavy magnesium users. Regular Epsom salt applications prevent the interveinal yellowing that signals Mg deficiency and improve fruit flavor and yield.

🌹

Rose Grower Staple

Rose growers have used Epsom salt for decades. ½ cup per plant in spring and fall produces more basal breaks, deeper green foliage, and more vigorous cane growth.

🌿

Foliar Spray for Fast Correction

2 tablespoons per gallon sprayed on foliage delivers magnesium directly through leaf stomata. Visible greening within 3–5 days on deficient plants.

📦

500 sq ft or 40 Gallons Per Bag

At 1 cup per 100 sq ft for soil application, one 5 lb bag covers ~500 sq ft. For liquid use, makes approximately 40 gallons of drench/spray solution.

✅

Safe & Natural

Magnesium sulfate is a naturally occurring mineral salt. Non-toxic, organic-compatible, and safe for all plants when used at recommended rates.

🇺🇸

Trusted by 20,000+ Growers

Developed in Littleton, New Hampshire. Sold nationwide on Amazon, Walmart, eBay, and theoldcobblersfarm.com.

NPK Ratio0-0-0
Derived FromMagnesium sulfate / Epsom salt (100%)
Item FormCrystalline granular
Release SpeedQuick-release (water soluble)
Application Rate1 cup / 100 sq ft (soil) | 2 tbsp / gal water (foliar/drench)
MethodBroadcast, dissolve for drench, or foliar spray
FrequencyEvery 2–4 weeks during growing season
Sizes5 lb | 10 lb | 15 lb | 20 lb
SupportsTomatoes, peppers, roses, lawns, houseplants, palms, all magnesium-deficient crops
SetupsGarden beds, raised beds, containers, lawns, greenhouses, houseplants, foliar spray
What We Love
✓ Instantly water-soluble magnesium and sulfur
✓ Foliar spray corrects deficiency symptoms in 3–5 days
✓ Essential for tomatoes, peppers, roses, and Mg-hungry crops
✓ 500 sq ft soil coverage or 40 gallons solution per bag
✓ Natural mineral salt — organic compatible, non-toxic
Worth Noting
— Zero NPK — not a fertilizer, purely a secondary nutrient supplement
— Overuse can create magnesium-calcium imbalance — soil test first
Buy on Old Cobblers Farm →
Available in 5 lb | 10 lb | 15 lb | 20 lb
Feature Old Cobblers Farm™ Wicked Organics Magnesium Sulfate Epsom Salt Plant Nutrient Agricultural Grade Epsom Salt Epsom Salts Magnesium Sulfate Magnesium Sulfate Epsom Salt Agricultural Grade Epsom Salt Epsom Salt (USP/Ag Grade) 100% Magnesium Sulfate Plant Food Agricultural Grade Epsom Salt Magnesium Sulfate Epsom Salt Epsom Salts Epsom Salt Agricultural Grade Epsom Salt Agricultural 100% Magnesium Sulfate Organic Magnesium Sulfate Plant Food Epsom Salt for Gardening Organic Earthworm Castings (no Epsom product) Langbeinite 0-0-22
NPK 0-0-0 Mg 9.8%, S 12.9% 100% MgSO₄ MgSO₄ (OMRI Listed) 100% MgSO₄ (OMRI Listed) 100% MgSO₄ 100% MgSO₄ (CDFA registered) 100% MgSO₄ (Ag Grade) 0-0-22
Phosphorus 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Potassium 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 22.0%
Form Crystalline granular
Sizes 5 lb | 10 lb | 15 lb | 20 lb 2, 5, 18 lb 5 lb 4 lb 1, 5, 10, 20, 25, 50 lb 1, 5, 10, 25, 50 lb 1, 5, 25, 50 lb 1.5 lb 32 oz (liquid) 5, 25, 50 lb
Release Speed Quick-release (water soluble)
The Competition

Epsom Salt Plant Nutrient

by Pennington
Mg 9.8%, S 12.9%
N-P-K
Price$10–$15 / 7 lb
Epsom salt is a commodity product with standardized analysis across all brands. **Pennington dominates big-box retail.** Monterey is the main OMRI-listed branded option at garden centers. Competition is primarily on price and distribution.

Agricultural Grade Epsom Salt

by Epsoak
100% MgSO₄
N-P-K
Price$33 / 18 lb
Epsom salt is a commodity product with standardized analysis across all brands. **Pennington dominates big-box retail.** Monterey is the main OMRI-listed branded option at garden centers. Competition is primarily on price and distribution.

Epsom Salts Magnesium Sulfate

by Monterey
MgSO₄ (OMRI Listed)
N-P-K
Price~$15 / 4 lb
Epsom salt is a commodity product with standardized analysis across all brands. **Pennington dominates big-box retail.** Monterey is the main OMRI-listed branded option at garden centers. Competition is primarily on price and distribution.

Magnesium Sulfate Epsom Salt

by CZ Garden Organics
100% MgSO₄ (OMRI Listed)
N-P-K
Price$13–$16 / 5 lb
Epsom salt is a commodity product with standardized analysis across all brands. **Pennington dominates big-box retail.** Monterey is the main OMRI-listed branded option at garden centers. Competition is primarily on price and distribution.

Agricultural Grade Epsom Salt

by PowerGrow Systems
100% MgSO₄
N-P-K
Price$14 / 5 lb; $30 / 25 lb
Epsom salt is a commodity product with standardized analysis across all brands. **Pennington dominates big-box retail.** Monterey is the main OMRI-listed branded option at garden centers. Competition is primarily on price and distribution.

Epsom Salt (USP/Ag Grade)

by Greenway Biotech
100% MgSO₄ (CDFA registered)
N-P-K
Price$12–$15 / 5 lb
Epsom salt is a commodity product with standardized analysis across all brands. **Pennington dominates big-box retail.** Monterey is the main OMRI-listed branded option at garden centers. Competition is primarily on price and distribution.

100% Magnesium Sulfate Plant Food

by Chemboys
100% MgSO₄ (Ag Grade)
N-P-K
Price$13–$16 / 5 lb
Epsom salt is a commodity product with standardized analysis across all brands. **Pennington dominates big-box retail.** Monterey is the main OMRI-listed branded option at garden centers. Competition is primarily on price and distribution.

Agricultural Grade Epsom Salt

by Epsoak
N-P-K
Sizes2, 5, 18 lb
Price$12-16 (18 lb)
Ingredients100% magnesium sulfate heptahydrate; ~10% Mg, ~13% S
OrganicUSP grade, Made in USA

Magnesium Sulfate Epsom Salt

by Cz Garden
N-P-K
Sizes5 lb
Price$14-18 (5 lb)
Ingredients100% magnesium sulfate; agricultural grade, Made in USA
OrganicOMRI Listed

Epsom Salts

by Monterey
N-P-K
Sizes4 lb
Price$10-14 (4 lb)
Ingredients100% magnesium sulfate; granular, water-soluble
OrganicGarden-labeled

Epsom Salt Agricultural Grade

by Greenway Biotech
N-P-K
Sizes1, 5, 10, 20, 25, 50 lb
Price$8 (1 lb), $20 (10 lb), $35 (25 lb)
Ingredients100% magnesium sulfate heptahydrate; 9.8% Mg, 12.9% S
OrganicAgricultural grade

Epsom Salt Agricultural

by PowerGrow
N-P-K
Sizes1, 5, 10, 25, 50 lb
Price$7 (1 lb), $25 (10 lb)
Ingredients100% magnesium sulfate; pH neutral, 100% water soluble
OrganicAgricultural grade

100% Magnesium Sulfate

by Chemboys
N-P-K
Sizes1, 5, 25, 50 lb
Price$12 (5 lb), $40 (50 lb)
Ingredients100% magnesium sulfate dry pellets; ag-grade tested
OrganicAgricultural grade, Made in USA

Organic Magnesium Sulfate Plant Food

by ENVY
N-P-K
Sizes1.5 lb
Price$8-10 (1.5 lb)
IngredientsMagnesium sulfate; water-soluble epsom salts
OrganicOrganic

Epsom Salt for Gardening

by EZ-GRO
N-P-K
Sizes32 oz (liquid)
Price$12-16 (32 oz)
IngredientsLiquid magnesium sulfate concentrate; professional formulation
OrganicProfessional grade

Organic Earthworm Castings (no Epsom product)

by Espoma
N-P-K
IngredientsNote: Espoma does NOT sell Epsom salt. Gap opportunity.

Langbeinite 0-0-22

by Down To Earth
0-0-22
N-P-K
Sizes5, 25, 50 lb
Price$13 (5 lb)
IngredientsNaturally mined langbeinite (K-Mag); potassium + magnesium + sulfur in one mineral
OrganicOMRI, CDFA OIM

🧪

9.8% Magnesium + 13% Sulfur

Two critical secondary nutrients in one water-soluble crystal. Magnesium drives chlorophyll production. Sulfur supports protein synthesis and flavor compound development.

💧

Instantly Water Soluble

Dissolves completely in water for immediate availability. Foliar spray delivers magnesium directly through leaf tissue for the fastest possible deficiency correction.

🍅

Tomato & Pepper Essential

Tomatoes and peppers are heavy magnesium users. Regular Epsom salt applications prevent the interveinal yellowing that signals Mg deficiency and improve fruit flavor and yield.

🌹

Rose Grower Staple

Rose growers have used Epsom salt for decades. ½ cup per plant in spring and fall produces more basal breaks, deeper green foliage, and more vigorous cane growth.

Common Questions