Water-Soluble Calcium (WCA) KNF Input, Eggshell Calcium for Blossom End Rot & Stronger Fruiting, 8 oz Makes 48 Gallons

🌱 Water-Soluble Calcium (WCA), Made on Our Farm

Water-soluble calcium, known across Korean Natural Farming as WCA (and sometimes WSC), is calcium delivered in the one form your plants can actually use. Most of the calcium already sitting in your soil is locked up as calcium carbonate, which roots cannot absorb. We convert eggshell calcium into a plant-ready liquid, so the moment you spray or drench it, your plants take it straight up to build firm cell walls, strong stems, and solid fruit.

Calcium is the structural mineral of the plant world, and a shortage shows up fast: blossom end rot on tomatoes and peppers, split or cracked fruit, weak stems, and leaves that bruise easily. A foliar mist of water-soluble calcium puts available calcium right where rapid growth is pulling it, which is why we lean on it as our plants move out of leafy growth and into flowering and fruiting. For the wider picture of how the inputs work together, see our master guide to KNF inputs.

We make this on our own farm in Colorado, and it is part of the input regimen that helped our soil reach a Haney Soil Health Score of 25.4, a number that surpasses the soil biology measured in pristine forest land. We farm soil-first because we believe healthier, more biologically alive soil grows stronger, more resilient plants, and this calcium input is one of the tools we use to get there. You can read the full story of how we built I·M·POSSIBLE Farm.

One 8 oz bottle goes a remarkably long way: at one teaspoon per gallon it makes 48 gallons of finished spray. New to natural farming? Our beginner's guide to KNF walks you through where calcium fits in the season.

Product Details

Specification	Detail
Product Type	KNF input, water-soluble calcium (WCA / WSC)
Calcium Source	Eggshell-derived (calcium acetate)
Format	Liquid concentrate
Size	8 oz bottle (makes 48 gallons diluted)
Dilution Rate	1 teaspoon per gallon (about 1:1000)
Application	Foliar spray or soil drench
Best Used	Fruiting and reproductive growth stage
Grade	Farm-made KNF input

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🌼 Frequently Asked Questions

What does water-soluble calcium actually do for my plants?

Calcium is the nutrient that builds strong cell walls, and strong cell walls are what give your plants firm stems, healthy roots, and solid fruit. The trouble is that most calcium already in your soil is locked in a form plants cannot absorb. Water-soluble calcium delivers calcium in a plant-ready form they can take up right away, which is why we reach for it as plants move into flowering and fruiting.

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Can this help with blossom end rot on my tomatoes and peppers?

Yes, that is one of the main reasons growers keep it on hand. Blossom end rot shows up when fruit cannot get enough usable calcium during rapid growth, and a foliar spray of water-soluble calcium puts that calcium right where it is needed. We get the best results applying it at the fruiting stage alongside steady, even watering, since calcium moves through the plant with water.

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Can I just make this myself with eggshells and vinegar?

You can, and we love that Korean Natural Farming is built to be shared. What you get from us is the exact eggshell calcium input we make on our own farm in Colorado, the same one that helped build soil with a Haney Soil Health Score of 25.4. It comes ready to dose at one teaspoon per gallon, so you can skip the weeks of roasting, crushing, and waiting and put it straight to work.

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How do I dilute it, and how far does one bottle go?

Mix one teaspoon into one gallon of water, which is about a 1:1000 dilution. At that rate the 8 oz bottle makes 48 gallons of finished spray. Apply it as a light foliar mist or a soil drench in the early morning or evening, and you can combine it with other KNF inputs in the same routine.