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Water-soluble calcium (WCA)

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Water-soluble calcium (WCA)

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Bioavailable calcium solution obtained from calcined eggshells and vinegar

Mineral and nutritional supplements Extract

Extract

Highly concentrated extraction of the plant material in a solvent (water, alcohol or oil), using a much higher plant-to-solvent ratio than a simple maceration, and often a longer contact time. The result is a very concentrated liquid, meant to keep for a long time and always be used diluted, unlike the other techniques prepared for more immediate use.

Process summary

1) Finely chop or crush the plant material, using a high proportion relative to the solvent (more plant matter than in a standard maceration). 2) Fully cover with the chosen solvent (water, alcohol or oil) in a closed container, opaque or kept in the dark. 3) Let it sit for several weeks, shaking occasionally. 4) Strain, bottle in a sealed container and store cool and dark — always use diluted, never undiluted.

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 ✅ Authorised (some countries)

A mineral solution rich in bioavailable calcium (calcium acetate), obtained by reacting calcined eggshells with vinegar. It provides soluble calcium that is easily absorbed by leaves and roots, an element that plays a role in the formation of cell walls.

Application

Application description: Dilute 1:500 to 1:1000 in water and apply as a foliar spray or to the soil, especially during flowering and fruit development, every 7–15 days.

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Regulatory status

✅ Authorised in the Philippines

Authorised bio-preparations: Philippines

A calcium supplement made from eggshells dissolved in vinegar for use as a fertilizer. Its production on the farm does not require European authorization (Regulation 2019/1009 only regulates marketing), but eggshells may be animal by-products subject to Regulation (EC) 1069/2009 depending on their origin. In organic farming, eggshells are listed in Annex II of Regulation 2021/1165, provided they do not originate from industrial livestock farming. Its ingredients also appear on the official lists of inputs permitted in organic farming of: Philippines. Depending on the country, some are only allowed under conditions (certification body approval, maximum doses): see each country's page.

Official texts

Official sources automatically checked on 20/10/2026.

What the icons mean: ✅ Authorised ⚠️ Tolerated 🟠 Not prohibited ⛔ Not authorised EU 🔎 Status being verified Full details →

Documentary information, checked on 19/10/2026. Not a substitute for legal advice; regulations may vary from country to country. See the regulations · Substances authorised in Europe

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