OGS Gypsum 1kg

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What is it?

Gypsum is a natural source of both Calcium and Sulfur (Calcium Sulfate) that corrects soil sodicity (too much Sodium). It improves the Calcium to Magnesium ratio of soil which in turn loosens the soil improving water infiltration, soil structure and Oxygen content.

The Sulfur in our Gypsum will enhance crop flavours and aromas, but also plays a vital role in nitrogen fixation (Sulfur is present in the important nitrogenase enzymes which contain a Fe-Mo-S cluster) and is used having ample glutathione as a catalyst for many vital plant processes. Sulphur is also involved in proper function of the immune system of plants via to combat oxidation stress. 

What are the benefits it provides?

  • Calcium is the workhorse of the plant. It shuttles other nutrients around the plant, Its availability to the plant is of incredible importance.

  • Sulfur is required in the production of both terpenes and resin. Having an abundance of Sulfur will allow for maximum terpene and resin production.

  • Improves soil tilth.

  • Improves water infiltration.

  • Helps prevent and correct soil sodicity (>15% Na in cation exchange complex).

  • Reduces surface crusting.

  • Increases yield and flavour.

  • Facilitates intensive transportation of macro-molecules around the plant during bloom. 

How do I use it?

Gypsum can be top-dressed, mixed into soil or used in watering, with NO negative impact on plant health. Gypsum can be applied in heavy doses with no issue and provide an intermediate length source of calcium and sulfur. Gypsum has a solubility of aprox 2g/ L at room temperature allow it to be used as immediately available organic source of Calcium and Sulfur.

We recommend at least 2 cups of Gypsum per 25L of Medium.                                                                                           

1 Cup per plant can be used mid cycle to treat calcium issues.

Returns Policy

You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.


We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

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