Gypsum
Gypsum
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Dispatched in 2 to 4 business days. Tracked courier delivery anywhere in New Zealand; bulk orders go by freight. Shipping is calculated at checkout.
Gypsum
Gypsum is natural calcium sulphate, a powdered soil amendment that supplies calcium and sulphur without changing soil pH. Use it to add calcium when pH is already right, to loosen clay, and to correct a calcium to magnesium balance a soil test shows is out.
At a glance
- Type: amendment (calcium sulphate)
- Supplier certificate on file: BioGro licence 297. See the certificate and its dates.
- Analysis: calcium (Ca) 22.00%, sulphur (S) 18.00%
- Use for: calcium and sulphur without a pH change, clay soils, high sodium soils
- Rate: 250 to 600 g per square metre, sized from a soil test
- Pack: bulk 500 kg and 1000 kg by quote
What it is
Gypsum is a naturally occurring mineral, calcium sulphate dihydrate, ground to a powder. 0.5 kg of gypsum is about 1 and two thirds cups; 1 kg is about 3 and two thirds cups.
Bulk is available in 500 kg and 1000 kg quantities. Email store@seaclifforganics.nz for a quote.
What it does
- Gypsum is calcium sulphate, a neutral salt. It supplies calcium and sulphur but does not neutralise acid, so it adds calcium without lifting pH.
- Calcium helps clay particles bind into crumbs, which is why gypsum is used to open up heavy clay and improve drainage and root depth.
- Calcium from gypsum displaces sodium from clay, the standard treatment for sodic soils.
- Gypsum dissolves slowly in soil water over months, releasing calcium and sulphur together. It is more soluble than lime, so its calcium moves down into the root zone.
- Sulphur builds proteins, oils and flavour compounds. A shortage shows as pale young leaves.
Analysis
- Sulphur (S) 18.00%
- Calcium (Ca) 22.00%
How to use
- Vegetables: 250 to 600 g (275 to 660 mL) per square metre of soil, sized from the calcium and sulphur shortfall on a soil test.
- Flowers: 250 g (275 mL) per square metre of soil.
- Modified media and potting soil: three quarters of a cup per 50 L.
- Soil test for optimum levels and for the calcium to magnesium balance before you apply. Our fertiliser calculator (/pages/fertiliser-calculator) offers gypsum at 250, 400 or 600 g per square metre for a tested shortfall.
- Gypsum does not raise pH. If the soil is acid and calcium is low, lime is the tool, not gypsum.
- Gypsum leaches in a wet climate. Retest after a couple of seasons rather than reapplying by habit.
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Handling and storage
- Wear a mask to avoid inhaling particles and open the bag in a well ventilated area.
- Wear gloves and eye protection, and wash hands after use.
- Once opened, keep sealed and dry.
Delivery and returns
Delivery and returns
We aim to dispatch within 2 to 4 business days. Bags go by tracked Courier Post (overnight target for main centres, 2 to 3 days rural). Cubes and tonnes go by Mainfreight or Move Logistics: 2 to 3 working days in the South Island, 3 to 7 days to the North Island. A rural delivery fee may apply.
Faulty, damaged or wrong items are repaired, replaced or refunded under the Consumer Guarantees Act, with return costs on us. Change of mind returns are accepted within 30 days of delivery for unopened products in original packaging (living products, bulk orders, testing, consulting and custom blends excluded). See returns and refunds and the FAQ.
Bulk and commercial orders
Bulk and commercial orders
Many products are available in cubes and tonnes, and living soil recipes can be modified to a specification. Email store@seaclifforganics.nz with quantities and delivery address for a price.
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