Healthy soil is the foundation of a successful farm. But when your crops start struggling, you may wonder: Should I use lime or gypsum?
Both improve soil, but they do very different things. Choosing the right one depends on what your soil actually needs.
Let’s break it down.
1. What Is Lime?
Hydrated lime (also called agricultural lime or calcium hydroxide) is made by treating quicklime with water. In fact, its main job is to raise the pH of acidic soils.
When your soil becomes too acidic, nutrients are much harder for plants to absorb. Fortunately, lime helps by neutralizing this acidity. As a result, it significantly improves nutrient availability and overall soil health.
Lime is ideal when your soil test shows a low pH.
2. What Is Gypsum?
Gypsum is a naturally occurring mineral made of calcium sulfate dihydrate. Unlike lime, it does not change soil pH. Instead, it’s commonly used to improve soil structure, particularly in clay or compacted soils.
Gypsum also helps remove excess sodium from sodic soils and adds valuable sulfur, which is an essential nutrient.
Use gypsum if your soil has poor drainage or high salt levels, but a neutral pH.
3. Key Differences Between Lime and Gypsum
| Feature | Lime | Gypsum |
|---|---|---|
| Changes soil pH | ✅ Yes – raises pH | ❌ No effect on pH |
| Main nutrients added | Calcium (sometimes magnesium) | Calcium + Sulfur |
| Used for | Acidic soils | Compacted, clay, or salty soils |
| Helps with | Nutrient uptake, soil biology | Soil structure, sodium removal |
| Best time to apply | When pH < 6 | When soil has poor drainage or high salt |
4. How to Know What Your Soil Needs
Before applying anything, do a soil test. It will tell you:
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pH level
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Sodium content
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Sulfur and calcium levels
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Soil type and texture
If the pH is low, lime is your answer.
If drainage is poor or salt is high, gypsum is better.
Sometimes, your soil may even benefit from both—just not at the same time.
5. Which One Should You Choose?
There’s no one-size-fits-all solution. But here’s a quick guide:
-
Use lime if your crops are underperforming and your soil is too acidic (pH below 6).
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Use gypsum if you’re battling hard, compacted, or salty soil, but your pH is already balanced.
Still unsure? Start with a soil analysis. It’s the best way to make the right decision and avoid wasting money.
🌾 Final Thoughts
Soil is complex—but choosing between lime and gypsum doesn’t have to be.
Both products improve soil performance; however, they do so in different ways. Therefore, if you correctly match the solution to the problem, you’ll see better yields, healthier crops, and smarter water use.
And if you’re working with acidic soils in southern Africa, Afri-Lime can help you get the right lime product for your land.
🔗 Want to Learn More?
Visit The Aglime Council for more expert resources on lime and soil management.
Blog:
🔍 Quick Glossary
Hydrated Lime:
A fine white powder made by adding water to quicklime. Used to raise soil pH and kill harmful microorganisms.
Gypsum:
A soft mineral (calcium sulfate) used to improve soil structure, reduce compaction, and lower sodium levels in the soil.
Soil pH:
A measure of how acidic or alkaline your soil is. A pH below 7 is acidic. Lime raises low pH.
Soil Compaction:
When soil particles are tightly packed, making it hard for water and roots to move through.
Sodic Soil:
Soil that contains too much sodium. It can block water absorption and harm crops.
Nutrient Availability:
How easily plants can absorb essential nutrients from the soil. pH plays a major role in this.
