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Wollastonite is gaining attention across Ontario farms as a dependable, multi-season soil amendment. While it’s best known in scientific circles for its carbon removal potential, for farmers, the benefits include improved pH stability, stronger crops, and healthier soil.
With mounting pressure from rising input costs and unpredictable weather, practical, low-intervention solutions that improve soil fertility are in demand. Wollastonite, a naturally occurring calcium silicate mineral, is one of them, and it’s already being applied to over 100 farms across eastern Ontario through UNDO’s farmer program.
What is Wollastonite?
Wollastonite is a mineral sourced and crushed in eastern Ontario through our partners at Canadian Wollastonite. This material provides calcium and silicon, two essential nutrients for agricultural soils. Its reaction with moisture and natural soil acids ensures a slow and sustained release of these nutrients.
It’s not a quick-fix input, but rather a long-term soil conditioner that supports healthier crop growth across multiple seasons. Unlike traditional lime, which can cause short-term swings in soil chemistry, wollastonite works steadily, helping to buffer pH and maintain more consistent conditions for plant roots.
The mineral has been used in industrial and horticultural applications for years, but it’s now being adopted by conventional row crop farmers across eastern Ontario, from mixed grain operations to market gardens and forage systems.
What Makes Wollastonite Different?
1. Improves Crop Resilience
Silicon is often missing from standard fertility programmes, not because it isn’t useful, but because many soils hold it in forms plants can’t use. Wollastonite changes that.
As it weathers, it releases plant-available silicon that strengthens cell walls and reinforces natural defences. Crops grown in silicon-rich soils are more likely to:
– Withstand heat, wind, and drought stress
– Resist fungal infections like mildew and blight
– Show fewer signs of insect damage
– Stand tall through harvest, reducing lodging risk
These benefits have been observed in real-world studies. For example, corn grown in wollastonite-treated soil saw 59% greater height and 90% more dry biomass than untreated plots. Beans responded even more strongly, with a 177% increase in dry biomass. In field trials conducted over three years, the application of calcium silicate to winter wheat reduced powdery mildew by up to 44% and increased grain yield by 10% compared to lime-treated plots.
Crops like squash, pumpkin, soybean, alfalfa, and rye have also shown measurable improvements, from better early growth to enhanced pest resistance.
2. Releases Calcium to Strengthen Plants
– Reduce issues like blossom end rot in tomatoes and squash
– Improve overall nutrient balance in soils where calcium is depleted
– Support root health in legumes and deeper-rooted grains
For farmers rotating between cash crops and cover crops, calcium also supports early germination and healthier root nodulation, setting the stage for better performance in subsequent rotations.
3. Supports Soil Structure and Nutrient Efficiency
Healthy soil holds nutrients, drains well, and stays workable. As wollastonite breaks down, it encourages better cation exchange, soil aggregation, and microbial activity, all of which support soil health and make other inputs work harder.
Several growers in the programme have reported:
– Less compaction and easier spring tillage
– Improved water retention in sandy or mixed soils
– More uniform early growth, especially in hay and forage crops
By gradually building soil resilience, wollastonite may reduce the need for additional nutrient corrections or synthetic inputs in future years.
4. Stabilises Soil pH Over Time
Maintaining balanced soil pH is essential for unlocking nutrients and keeping crops performing season after season. But lime applications can wear off quickly, especially in lighter soils or wetter regions.
Wollastonite works differently. It doesn’t create a dramatic pH shift, instead, it buffers soil pH steadily, helping you avoid seasonal drops that limit uptake of nitrogen, phosphorus, and potassium. Research shows it takes around 1.2 tonnes of wollastonite to match the liming effect of 1 tonne of lime, but the impact often lasts longer due to slower weathering.
This makes it ideal for fields where pH creeps down between applications, particularly hay fields, pastures, and lower-fertility paddocks.
5. Lasts Longer Than Conventional Amendments
Unlike fast-release fertilizers or lime, wollastonite offers a multi-season benefit. It doesn’t need to be applied every year, many farmers see improvements well into their second or third growing season after application.
This makes it well-suited to long-term soil improvement strategies. Whether you’re looking to boost perennial pastures, prepare ground for transition crops, or reduce correction costs down the line, wollastonite offers a practical return on your spreading investment.
“I’ve been applying wollastonite for 8 years, and my fields keep getting better. I get less lodging, and my crops grade higher. Yields are up overall, and the crops seem to handle the weather extremes better. From sod to corn I use wollastonite on a wide variety of crops. Signing up for the carbon project was straightforward. The fact that wollastonite captures carbon is a nice bonus for the planet.”
Matt Gauthier
Farm Manager, Ontario
Want to learn more about the agricultural benefits? Learn more here.
How the UNDO Farmer Program Works
UNDO’s farmer program is designed to make trying wollastonite simple and low-risk. Thanks to our partnership with Canadian Wollastonite, eligible farms can access the material at no cost, covering only haulage.
Here’s what the programme includes:
– Subsidised Costs: No charge for the wollastonite itself, only haulage
– Logistics support: We help with coordination, scheduling and spreading
– Ongoing support: We stay in touch to help assess outcomes over time
Eligibility: Farms within approximately 150 km of Seeley’s Bay are eligible. We typically look for soil pH between 6.0 and 7.0 to enhance its carbon removal potential, though in some cases we can work slightly outside that range based on soil conditions and spreading goals.
If you’re unsure whether wollastonite is right for you, get in touch with us.
Application and Timing of Wollastonite
Wollastonite can be applied with standard lime spreaders or dry fertilizer applicators. Most growers apply it:
– Ahead of spring planting
– Post-harvest as part of field prep
– On pasture or after a hay or silage cut
– Alongside other dry soil amendments
Because it breaks down gradually, wollastonite doesn’t require repeated application every year. Most farms in the programme apply it on a 2–3 year cycle, depending on crop rotation and initial soil pH.
Thinking About Trying Wollastonite?
If you’re looking for a reliable, field-tested way to build healthier soils and reduce reliance on corrective treatments, wollastonite is worth considering. It’s simple to apply, backed by evidence, and available through a supported programme with no upfront product cost.
At UNDO, we work with farmers, not around them. Whether you’re managing a mixed operation, livestock integration, or a tight rotation, our team will help assess whether wollastonite fits your land, your crops, and your season.
To learn more or check your eligibility, get in touch directly with our team.
Let’s make your soils work harder, for longer.
Interested in trying wollastonite on your farm?
We’re already working with over 100 farms across Ontario. If you're curious about how wollastonite could support your soil health and crop performance, we’d love to hear from you.
