Gypsum 21% Soil Conditioner | Clay & Compaction Support

The Lawn Medic | Calcium-rich soil amendment that improves soil structure and reduces compaction.

★★★★★ 4.8 stars on over 5,000 orders

Gypsum 21% | Soil Conditioner for Clay & Hard Soil

$29.00

SGN 150 Mini Prill Made for Canada Pro Grade Spreader Ready

"The fertilizer worked amazing. Lawn was super green all year. Will definitely be purchasing again." - Brent S.

Bag Size: 2kg

2kg
5kg
10kg

Product variants

Coverage (selected size)

Covers up to 462 sq ft

In stock, ready to ship

Pickup available at Pickup Location UPS STORE

Usually ready in 24 hours

100% Organic

A completely organic fertilizer that provides your lawn important nutrients without synthetic products. It can be used individually or part of a full season organic program.

Open up tight soil and improve drainage without changing pH. Gypsum (21% calcium) helps loosen heavy clay, improve soil structure, and support healthier root growth for lawns and gardens.

0-0-0-21Ca

NPK

Mini - SGN 150

Prill Size

Granular

Application Type

Best For

Clay-heavy lawns, compacted garden beds, and areas that puddle or dry hard after rain.

What Makes It Different

Gypsum works differently than many soil amendments because it improves soil structure without significantly changing soil pH. The calcium helps loosen compacted soil and encourages better aggregation of soil particles. This improves drainage, aeration, and root penetration, making it particularly valuable for clay soils or heavily compacted areas.

Application Rate

4.3kg (9.5lbs) to 8.7kg (19lbs) per 1000sqft per application

Minimum Guaranteed Analysis

• Sulfur (S) – 16%
• Calcium (Ca) – 21%

Product Details

NPK | 0-0-0-21Ca
Nitrogen Release | Balanced | Immediate break down into the soil
Prill Size | Micro Prill | SGN 90 | The smallest prill size offering the most even and fastest results
Application Type | Granular | Apply with any lawn spreader

Storage & Handling & Safety

Storage

We recommend keeping your seed in a cool dry location, especially after opening. This helps to maintain a high germination rate for an extended period of time.

Handling

Seed is safe to handle. However if you are sensitive to airborne particles you may want to wear a mask when adding your seed to a spreader for instance.

Shipping & Returns

Shipping

We ship Canada wide. Most orders are shipped with UPS. Canada Post is used for some locations.

Shipping on Grass Seed is always free. Shipping on fertilizers is calculated based on weight.If your order combines seeds and fertilizers you will only be charged for the weight of the fertilizer. We do our best to offer a balance between fast shipping and reasonable shipping rates.

We strive to ship all orders within 24hrs (48hours max).

Please reach out to use if you have any questions.

Returns

All of our products can be returned within 30 days as long as it is unopened/unused.

If you have a concern with your product after opening it please reach out to use as we always work to find a solution and rectify any issues.

Share:

Share

Shipping Credit on Fertilizers

Spend $200, Get $20 Shipping Credit
Spend $300, Get $30 Shipping Credit
Spend $400, Get $40 Shipping Credit
Spend $500, Get $50 Shipping Credit

Valid on individual fertilizers only. Grass seed is always free shipping.

Pairs well with

In stock! Ships within 1-2 business days.

Expedited shipping on all orders.

Only professional grade fertilizers.

30-Day Return Policy

Gypsum 21% | Soil Conditioner for Clay & Hard Soil

2kg

$29.00

A Better lawn starts here

Don't Take Our Word For It

See what our happy customers are saying about how The Lawn Medic helped their lawns.

See All Our Reviews

Expedited Shipping on All Orders

Why This Fertilizer?

Gypsum is widely used as a soil conditioner to improve soil structure and root development. The calcium in gypsum helps loosen compacted soils and encourages better aggregation of soil particles. This improves drainage, aeration, and root penetration. Unlike lime, gypsum does not significantly raise soil pH, making it useful in a wider range of soil conditions. Improving soil structure allows roots to grow deeper and access more water and nutrients, leading to healthier turf over time.

Technical Details

Gypsum is commonly used as a soil amendment to improve soil structure and reduce compaction in certain soil types. The calcium supplied by gypsum promotes flocculation of soil particles, helping clay soils form more stable aggregates. Research conducted through the Penn State Center for Turfgrass Science shows that improved soil aggregation enhances water infiltration and root penetration.

Unlike lime, gypsum does not significantly alter soil pH. This allows it to improve soil structure without affecting soil chemistry. Improved soil structure allows turfgrass roots to grow deeper and access water and nutrients more effectively.

See the difference

Geoff D.

"I used seed and fertilizer from The Lawn Medic in the Spring. The transformation over about 5 weeks was incredible. The pictures tell the story. The new lawn came in thick and green and it has stayed that way all year. No weeds. Strong growth."

Testimonials

"Best result I've ever had in reseeding my lawn. No more big box branded lawn seed with pathetic results. Next fall will be the backyard's turn."
— Jose C.

"Lawn looks freaking awesome in December 😄😄 Will definitely be ordering again in the spring."
— Daryl F.

"Despite this summer’s heat and drought, the lawn stayed healthy. The seed quality is noticeably better than what I’ve bought from big-box stores."
— Ryan C.

FAQs

Please read our FAQs page to find out more.

What makes your products better?

All of our products, including our seeds and fertilizers, were developed for professional uses. This means that you are truly getting the best of the best when it comes to lawn care products. Forget the big box store products and try what the pros use.

Do you provide guides on how to use your products?

Yes, of course we do. Take a look at our Guides page. We will be adding more guides and helpful tools soon as well.

Can you help me decide what I need?

Yes! We are here to help. Contact us anytime with your questions and we will get back to you within 1-2 days with some suggestions. We also have our Guides page which can answer some questions, and we have more helpful tools coming soon.

How can I get your products?

We ship Canada wide by UPS and Canada Post (it depends on the location). Every shipment is expedited to arrive as soon as possible, and ships within 1-2 days. We also have a pickup location in Burlington, Ontario.