Epsom Salt
Magnesium sulfate crystals dissolved in water that correct magnesium deficiency, the most common cause of interveinal leaf yellowing in garden crops.
What it is
Epsom salt is the common name for magnesium sulfate heptahydrate, a naturally occurring mineral compound mined from underground salt deposits. It is approved for organic production as a targeted magnesium supplement. It is highly water-soluble and provides both magnesium and sulfur in plant-available forms.
What it does
Magnesium is the central atom in the chlorophyll molecule and is essential for photosynthesis, enzyme activation, and the uptake of phosphorus and nitrogen. A deficiency causes the characteristic interveinal chlorosis - yellowing between the leaf veins on older leaves while the veins remain green. Epsom salt corrects this deficiency quickly when applied as a foliar spray or root drench.
When to use
Apply when interveinal yellowing on older leaves suggests magnesium deficiency, or preventively on heavy-cropping plants such as tomatoes, roses, and peppers known to be magnesium-hungry. Foliar application is the fastest route to correction. As a preventive, apply once at planting and again at mid-season on susceptible crops grown in light, sandy soils.
When not to use
Do not apply Epsom salt to plants showing nutrient problems without first confirming that magnesium is the deficient element, as excessive magnesium can compete with calcium and potassium uptake and worsen other imbalances. Avoid repeated use on soils that already test high in magnesium, which is common in heavy clay soils.
How to apply
- 1
For foliar spray, dissolve 1 tablespoon of Epsom salt in 1 quart of warm water and stir until fully dissolved.
- 2
Apply to all leaf surfaces in the early morning using a fine mist sprayer, ensuring thorough coverage of both upper and lower leaf surfaces.
- 3
For a soil drench, dissolve 2 tablespoons per quart and apply 1 - 2 quarts around the root zone of each affected plant.
- 4
Repeat the foliar application every 2 weeks until symptoms resolve. Repeat the soil drench once a month if needed.
- 5
Continue monitoring for improvement. Yellowing should begin to reverse within 2 - 3 weeks as new and existing leaves respond to the magnesium supply.
Garden, by Willowbottom recommends only organic, wildlife-friendly solutions. No synthetic pesticides, no harmful chemicals - ever.