Can Epsom salts prevent all tomato nutrient problems?
Written by
Paul Reynolds
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Epsom salts can't solve all of your tomato nutrient problems, as many people believe. They correct magnesium deficiencies but can exacerbate other deficiencies. I have seen gardens where the use of too much Epsom salts resulted in Calcium lockout and blossom end rot. Always check for magnesium deficiency before applying any.
Ineffective Deficiencies
- Nitrogen: Shows as uniform yellowing of older leaves
- Phosphorus: Causes purpling stems and stunted growth
- Potassium: Creates scorched leaf margins and weak stems
- Requires complete NPK fertilizers instead
Harmful Applications
- Worsens calcium deficiency causing blossom end rot
- Triggers magnesium toxicity above 400 ppm soil levels
- Disrupts potassium-magnesium balance in plant tissues
- In sandy soils accelerates leaching of other nutrients
Proper Verification
- Soil test mandatory before any Epsom salts use
- Confirm magnesium levels below 50 ppm for deficiency
- Check calcium-to-magnesium ratio exceeds 3:1
- Tissue test oldest leaves showing 0.3-0.6% magnesium
Correctly recognize magnesium deficiency! True cases show first interveinal chlorosis in older leaves. Nitrogen deficiencies result in variable yellowing of all leaves, while phosphorus deficiencies tend to cause purple stems. Burned tips of leaves characterize potassium deficiency. I use diagnostic flowcharts, which save trouble from incorrect application.
Prevent the threat of brain lesions in humans and animals (11) by maintaining low magnesium levels in the soil. Never exceed 300 ppm in soil test. Apply not to exceed *four* foliar sprays per season. I stop applying as soon as I see new growth that doesn't show the effects of Mg burn. Overuse will result in malformation of the leaves (dark, curled) and stunting of the plants. The stunted plants require months for recovery.
Strategically use Epsom salts in combination with other amendments. After correcting magnesium, I apply compost to replenish micronutrients. I use balanced organic fertilizers to maintain harmony in the nutrient environment. This overall approach boosts plant health without creating new imbalances.
Document all applications in detail. Record the dates, rates, and plant responses in a garden journal. Each year, I review these notes to refine my practices. I find that this process minimizes the likelihood of repeating mistakes and also develops sustainable and effective soil management strategies.
Read the full article: Magnesium Deficiency Tomatoes: Complete Grower Guide
