Sources of Agricultural Limestone

When comparing limestone from different suppliers, be sure to ask for the following information:

1. Type of limestone: Is it either calcitic or dolomitic? Calcitic limestone consists mostly of calcium carbonate. Dolomitic limestone is a mixture of both calcium and magnesium carbonates. Dolomitic limestone should be used on soils with a magnesium soil test of 100 ppm or less. It is an excellent and inexpensive source of magnesium for acidic soils. On soils with a magnesium test greater than 100 ppm calcitic or dolomitic limestone may be used.

2. Guaranteed Minimum Specifications: This will provide the per cent calcium, percent magnesium, neutralizing value, fineness rating and Agriculture Index.

3. Neutralizing value (NV): NV compares the ability of the limestone to neutralize acidity relative to pure calcium carbonate. It is expressed as a percent of calcium carbonate's ability to neutralize acidity. Relative to calcium carbonate, a value less than 100 is less effective, while greater than 100 are more effective. The NV generally increases as the calcium and magnesium content increases.

4. Fineness rating: To be effective limestone must dissolve. A limestone's fineness rating is a measure of its particle size distribution and is determined using sieves. Any material passing through a #60 sieve is consisted to be fully effective. Material that passes through a #10 sieve but not #60 is considered only 40% effective. Materials that do not pass through #10 sieve are considered ineffective.

5. Agricultural Index (AI): AI is an indicator of a limestone's ability to neutralize acidity. It is calculated using the neutralizing value and fineness rating. It can be used to compare the ability of different limestones to neutralize soil acidity. The higher the AI the more effective the limestone on an equal weight basis. The average AI of limestone sold in Ontario has been about 75.

For more information about limestone, managing soil pH with lime, neutralizing value, fineness rating, calculating the Agriculture Index and determining the amount of lime to apply can be found in OMAFRA Publication 811 Agronomy Guide for Field Crops, Chapter 9.

Suppliers of Agricultural Limestone

This supplier list does not imply any endorsement or recommendation by the Ontario Ministry of Agriculture, Food and Rural Affairs.

For specific questions regarding the limestone analysis or specifications, please contact the appropriate company for their latest analysis information.

CBM Aggregates

546 Thomas St.
St Mary's, ON N0M 1V0
Telephone: 519-831-9492

Coloured Aggregates Inc.

158 Don Hillock Drive, Unit 12-13
Aurora, ON L4G 0G9
Telephone: 1-800-465-5066; 905-727-7100
Fax: 1-905-727-0060

Dufferin Aggregates

2300 Steeles Avenue West, 4th Floor
Concord, ON L4K 5X6
Telephone: 1-855-225-5332, 1-877-332-3006

E.C. King Contracting

2125 20th Ave. East
P.O. Box 457
Owen Sound, ON N4K 5P7
Telephone: 519-376-6140
Fax: 519-371-2783

Graymont (QC) Inc.

206-25, De Lauzon Street
Boucherville, QC J4B 1E7
Telephone: 450-449-2262

Miller Minerals

P.O. Box 248
New Liskeard, ON P0J 1P0
Telephone: 705-672-2282
Fax: 705-672-2746

Omya Canada Inc.

Box 245, 18595 Highway 7 W.
Perth, ON K7H 3E4
Telephone: 613-267-5367
Fax: 613-267-5408

R.W. Tomlinson Ltd

100 Citigate Dr,
Ottawa ON, K2J 6K7
Telephone: 613-690-3012
Cell: 613-223-2858
Fax: 613-822-6844
Website :

Sudbury Lime Limited

300 Kukagami Road
Wahnapitae, ON P0M 3C0
Telephone: 877-682-2958

Walker Brothers Quarries

Niagara Falls Quarry - 2800 Thorold Townline Rd,
Niagara Falls, ON L2E 6S4

Vineland Quarry - 3614 Fly Rd,
Vineland, ON L0R 2C0

Phone number for both Niagara sites: 905-680-3755
Fax: 905-227-1034
Email for both Niagara sites:

Walker Aggregates - McGregor Quarry

6781 North Side Road,
Amherstburg, ON N9V 2Y9
Phone: 519-736-2136

Walker Aggregates - Severn Pines Quarry

2646 Nichols Line,
Orillia, ON L3V 6H3
Telephone: 844-680-3757

Walker Aggregates - Keppel Quarry

178763 Grey Rd 17,
Owen Sound, ON N4K 5N4
Telephone: 519-376-5698

For more information:
Toll Free: 1-877-424-1300