A Complete Guide to Testing, Choosing, and Applying Lime for Healthy Garden Soil
Healthy plants start with healthy soil—and one of the most important factors in soil health is pH. If your soil is too acidic, your plants can struggle to absorb essential nutrients, even if they’re present in the soil. That’s where lime comes in.
In this guide, you’ll learn everything you need to know about adding lime to acidic soil: what it is, when and why to use it, how to test your pH, how much to apply, and how to apply it safely and effectively.
🧪 Why Soil pH Matters
Soil pH measures how acidic or alkaline your soil is on a scale from 0 (very acidic) to 14 (very alkaline), with 7 being neutral.
- Most vegetables, herbs, and flowers prefer a pH between 6.0 and 7.0.
- Acidic soil (below 6.0) can reduce nutrient uptake and promote fungal diseases.
- Some crops (like blueberries, potatoes, and rhododendrons) prefer acidic soil—but for most garden plants, overly acidic soil can stunt growth.
🍋 What Is Lime?
“Lime” in gardening refers to ground limestone, not the citrus fruit! There are two main types used to adjust pH:
1. Calcitic Lime
- Made from crushed limestone (calcium carbonate)
- Adds calcium to the soil
2. Dolomitic Lime
- Contains both calcium carbonate and magnesium carbonate
- Best for soils low in magnesium
Both types work to raise soil pH and help balance mineral availability.
📏 Step 1: Test Your Soil pH
Before adding anything to your garden, it’s important to know your starting point.
How to Test:
- Use a home pH test kit or digital pH meter
- Or send a soil sample to your local cooperative extension office for a full nutrient profile
Test soil from multiple areas and depths for the most accurate reading. Your soil may have variations in pH depending on previous amendments, rainfall, and plant types.
General pH Recommendations:
- 🌿 Most garden veggies: 6.2–7.0
- 🍓 Strawberries: 5.5–6.5
- 🫐 Blueberries: 4.5–5.5
- 🥔 Potatoes: 4.8–6.0
If your pH is below 6.0 and you’re not growing acid-loving plants, you’ll benefit from lime.
🧮 Step 2: Determine How Much Lime to Use
The amount of lime needed depends on:
- Current soil pH
- Desired pH range
- Soil type (sand, loam, clay)
- Type of lime used (calcitic vs. dolomitic)
General Guidelines (per 100 sq ft):
| Soil Type | Raise pH by 1 point | Ground Limestone Needed |
|---|---|---|
| Sandy | From 5.5 to 6.5 | 4–5 lbs |
| Loamy | From 5.5 to 6.5 | 7–8 lbs |
| Clay | From 5.5 to 6.5 | 8–10 lbs |
Pro Tip: It’s better to apply less lime more often than too much at once. Over-liming can push your soil too far the other way.
🌾 Step 3: Apply Lime to Your Soil
When to Apply:
- Fall or early spring are best
- Lime takes 2–6 months to fully change soil pH
- Applying in fall gives time for the soil to absorb and adjust
How to Apply:
- Clear the bed of plants, mulch, or debris
- Spread lime evenly over the soil surface
- Work it into the soil 6–8 inches deep using a garden fork, tiller, or broadfork
- Water lightly to help the lime activate
If your garden is already planted:
- Sprinkle lime around the base of plants
- Lightly scratch into the top inch of soil
- Water it in
For containers, add lime when preparing the potting mix—not on top of existing potted plants unless carefully calculated.
⚠️ Safety Tips
- Wear gloves and a dust mask when applying powdered lime
- Avoid breathing in lime dust or letting it blow into your eyes
- Wash hands and tools after use
🧠 Extra Tips for Success
- Don’t use hydrated lime (calcium hydroxide) in the garden—it’s highly caustic
- Check your pH again 2–3 months after liming to see results
- Be patient—lime is not a quick fix, but long-term soil health is worth it
- Pair lime application with compost or organic matter for even better soil conditioning
🌻 Final Thoughts
Correcting acidic soil with lime is one of the most impactful things you can do for your garden’s health. When your soil pH is in balance, your plants are better able to take in the nutrients they need to thrive—and that means bigger harvests, stronger roots, and more resilience to pests and disease.
With a little testing, timing, and elbow grease, you can naturally balance your soil and help your garden grow better, the organic way.