Strengthening Plants and Soils with Silicon-Rich Wollastonite

Crop diseases are a familiar threat to yields across Canadian farms. Whether it’s root rot stunting vegetables or mildew stripping foliage, fungal infections can cause lasting damage. Chemical treatments like fungicides have their place, but more farmers are exploring long-term, soil-based approaches to disease management, particularly those that build natural resilience from the ground up.

Wollastonite is one such amendment gaining attention. This naturally occurring calcium silicate mineral not only raises soil pH, but also delivers silicon to plants, a mineral that plays a key role in strengthening plant defences. Silicon has been shown to reduce disease severity across a range of crops by reinforcing plant structures, stimulating internal resistance mechanisms, and helping crops recover faster from stress and infection.

Wollastonite provides a practical way to make silicon available in the field. It spreads easily using standard lime equipment, integrates into current rotations without disruption, and delivers benefits that last for multiple growing seasons.

What Does Silicon Do In A Plant?

Silicon is the second most abundant element in the Earth’s crust, but most of it is in forms unavailable to plants. When supplied in a soluble form, like the kind released gradually by wollastonite, silicon can be absorbed through the roots and transported throughout the plant.

Once inside, silicon gets to work in a few key ways:

– Physical defence: It’s deposited in the cell walls of leaves, stems, and roots, creating a more rigid barrier that makes it harder for fungal pathogens to penetrate.

– Internal resistance: Silicon helps the plant recognise pathogens more quickly and mount a stronger immune response, producing antifungal compounds and stress-related signals.

– Stress recovery: Crops with sufficient silicon are more resilient under drought, heat, or disease pressure, helping them recover faster and maintain productivity.

This combination of physical and biochemical support gives silicon a unique advantage. Rather than killing off pathogens directly, it boosts the plant’s own ability to resist and tolerate them. That makes it especially valuable in situations where disease pressure is high or chemical tools are limited, like in organic or low-input systems.

The Science Behind Silicon’s Disease Suppression Benefits

Researchers have studied silicon’s effects on disease for decades. What’s clear is that it plays a consistent and positive role in helping plants resist infection.

In one controlled study, tomato seedlings were grown in sand culture with and without silicon, then exposed to Fusarium oxysporum, the fungus responsible for Fusarium crown and root rot. Tomatoes treated with silicon showed significantly reduced symptoms, less browning and wilting in the stem, and less spread from the root to the crown. Importantly, the silicon-treated plants had higher concentrations of silicon in their tissues, especially in the roots, and this correlated directly with lower disease severity.

Another study on pumpkins looked at resistance to powdery mildew, a foliar disease common across many cucurbits. Researchers tested different rates of wollastonite and found that moderate applications (between 3.13 and 6.25 tons/acre) led to higher silicon uptake and stronger resistance. These same rates also adjusted the soil pH to optimal levels for pumpkin production, showing that wollastonite can deliver both soil fertility and disease protection benefits.

Across these and other trials, the pattern is clear: when silicon is available, crops are better equipped to stand up to disease. And because wollastonite is a slow-release source of silicon, a single application can support plant health over multiple seasons.

What Crops Benefit Most?

Not all crops take up silicon equally. Species like wheat, barley, rice, cucurbits (pumpkin, cucumber, squash), tomatoes, and peppers are among the best silicon accumulators. These are also the crops where the strongest disease suppression benefits tend to be seen.

For these crops, added silicon from wollastonite can:

– Reduce the incidence and severity of fungal root diseases like Fusarium and Pythium

– Decrease foliar disease pressure from mildew and blight

– Improve root structure and nutrient uptake

– Increase tolerance to drought and other abiotic stresses

– Enhance biomass and overall vigour

Crops that are not strong silicon accumulators may still benefit indirectly, through improvements in soil pH and overall growing conditions, but the direct disease suppression effects are most pronounced in silicon-accumulating plants.

Wollastonite Vs Traditional Lime: More Than pH

Many Canadian farms already apply lime to neutralise acidic soils. Wollastonite offers a similar liming effect, with one important difference: it also adds plant-available silicon. This extra value can support better crop outcomes, particularly where disease suppression and stress tolerance are important.

Like lime, wollastonite improves nutrient availability by raising soil pH into the optimal range for crop uptake. But unlike lime, it slowly releases silicon into the soil solution, making it available for root uptake over time. This means a single application can deliver longer-term benefits than lime alone, especially when applied at the right rate for pH correction.

In pumpkin trials, wollastonite and limestone had comparable effects on pH. But only wollastonite raised tissue silicon levels and reduced powdery mildew severity. This shows that when choosing a liming product, the source matters; wollastonite brings more to the table.

Best Practices For Applying Wollastonite

Wollastonite can be spread using the same equipment used for lime. It’s dry, granular, and easy to apply, either before planting or as part of a fall or early spring application. Because it’s slow-acting, it doesn’t require annual reapplication. Many growers see benefits for multiple seasons from a single spread.

UNDO’s field team works with each farm to determine the right rate and timing for your operation. And because the product is subsidised through the UNDO farmer program, the only cost to the grower is haulage, making it a low-risk option to try on your own land.

A Practical Option For Organic And Low-Input Systems

Disease management is particularly tough in organic systems. Fewer chemical options, greater risk of resistance, and tighter cost margins mean that prevention is often the best cure. That’s where silicon’s mode of action fits well.

Wollastonite is listed for use in organic production. It integrates easily into certified systems, without changing rotations or requiring special handling. And because it helps plants mount their own defence, it complements other organic practices like compost use, crop rotation, and biological treatments.

For conventional growers, wollastonite can also help reduce reliance on fungicides or make them more effective by reducing background disease pressure. Either way, it’s a smart addition to an integrated disease management strategy.

Why More Canadian Growers Are Turning To Silicon

The pressure on yield and quality is only increasing. Weather extremes, shifting disease patterns, and tighter margins are pushing growers to get more from their inputs while reducing long-term risks. Wollastonite offers a way to meet multiple goals at once: healthier soils, stronger plants, and reduced disease.

In practical terms, Canadian growers using wollastonite have seen:

– Better early crop establishment

– Reduced symptoms from common fungal pathogens

– Improved leaf health and standability

– Less pressure from diseases like mildew and Fusarium

– Stronger returns over time from a one-time application

When soils are acidic and disease pressure is high, wollastonite offers a simple, cost-effective way to improve both.

Available Through The UNDO Farmer Program

Eligible growers in Ontario can access high-quality crushed wollastonite through the UNDO farmer program, with spreading support and no changes needed to rotation or equipment.

The only cost is haulage. Everything else, from advice to material to verification, is covered through the program. And by taking part, you’re not just improving your own soil, you’re contributing to a broader climate solution by enabling carbon removal through enhanced rock weathering.

Interested in trying wollastonite on your farm?

UNDO’s farmer program makes it easy to get started. We provide high-quality crushed wollastonite at a subsidised rate, with no changes to your current rotation or equipment. You only cover the cost of haulage, we take care of the rest.

Speak to our team