Limestone (Coarse Grade)
Coarse limestone is a natural calcium source that breaks down slowly in the soil, helping to improve soil conditions and maintain balanced pH over time.
Designed for long-term soil conditioning, coarse limestone provides a steady supply of calcium while gradually reducing soil acidity. This creates a more stable growing environment and supports improved nutrient availability.
Calcium plays a critical role in plant development, supporting strong cell walls, healthy root growth, and overall plant resilience.
Benefits
- Adds calcium for strong, healthy plant growth
- Helps raise and maintain balanced soil pH over time
- Improves the availability of phosphorus
- Lower in magnesium compared to dolomitic lime
- Supports beneficial soil microbial activity
- Provides long-lasting soil conditioning
Coarse vs. Fine Limestone
Coarse grade is best suited for building and maintaining soil health over time. Coarse limestone breaks down slowly for long-term soil improvement. Fine or granulated limestone reacts more quickly for faster pH adjustment
Application
Garden & Small Areas
Apply 500 g – 1 kg per 10 m² (1–2 lbs per 100 ft²). For best results, incorporate into the soil where possible.
Field Application (Agricultural Use)
Apply 1–2 tons per acre depending on soil conditions and pH levels. For best results, incorporate into the soil prior to planting.
Soil pH Management
Most plants prefer a soil pH between 6.0 and 7.0. Because coarse limestone reacts gradually, apply in advance of planting or as part of a long-term soil improvement program.
Soil Testing Recommended
Limestone application should be based on soil conditions. Applying without testing can lead to over-liming, which may reduce nutrient availability.
Our laboratory soil analysis includes sampling, detailed results, and tailored application recommendations—so you know exactly what your soil needs and how much to apply.
Understanding Soil pH, Calcium, and Heavy Metals
Aluminum is naturally present in most soils, but under acidic conditions it dissolves into a form that plants can absorb. In this soluble form, aluminum damages root tips—limiting growth, water uptake, and nutrient access.
Applying limestone supplies calcium and raises soil pH, which makes aluminum (and other heavy metals) far less available to plants. The result is deeper, stronger roots that use nutrients more efficiently.
How Calcium Helps Limit Heavy Metal Uptake
Calcium reduces heavy metal uptake in three key ways:
1. Raising Soil pH
In acidic soils, metals are more soluble and easier for plants to absorb. Limestone helps keep more of these metals bound in the soil rather than entering the plant.
2. Competing at the Root Level
Calcium shares the same uptake pathways as metals like cadmium, lead, and nickel. When sufficient calcium is present, plants absorb more calcium and less of these competing metals.
3. Strengthening Root Systems
Calcium fortifies cell walls and root membranes, helping roots better regulate what enters the plant and reducing passive uptake of unwanted elements.
Heavy Metals Most Affected
Improving soil pH and calcium levels can help reduce the availability and uptake of:
- Cadmium (Cd)
- Lead (Pb)
- Nickel (Ni)
- Zinc (Zn)
- Aluminum (Al)
- Manganese (Mn)
Why This Matters
Healthy soil isn’t just about nutrients—it’s about balance. By supplying calcium and improving soil pH, limestone helps create a more stable soil environment where plants can grow efficiently, access nutrients, and limit the uptake of unwanted elements—supporting cleaner, healthier crops.
Typical Analysis
- Calcium Carbonate (CaCO₃): 97.38%
- Calcium (Ca): 54.57%
- Magnesium (Mg): 0.72%
DOWNLOAD - COARSE LIMESTONE LAB ANALYSIS (PDF)
DOWNLOAD - ORGANIC DECLARATION LIMESTONE (PDF)
This product complies with Canada’s Organic Production Systems General Principles & Management Standards and Permitted Substances Lists (CAN/CGSB-32.310-2021 CAN/CGSB-32.311-2020)
