How it works
Place the eggshells on a baking sheet and heat in the oven at 200°C for 20 minutes. This will make them more brittle and release the nutrients more easily.
Place eggshells in a glass and crush them with a spoon or spatula. The glass should be one-fifth full of crushed shells.
Pour the apple cider vinegar into the jar to within 2–3 cm of the rim. The mixture may foam, so place the lid loosely on the jar and place the jar in the bowl to catch any overflow.
Do not place the bowl and jar in direct sunlight, but store them in a well-ventilated place with a constant temperature for two weeks.
Then pour the liquid into the second jar using a sieve, screw on the lid and label it.
The liquid contains a highly concentrated form of calcium, so you only need 5–10 ml (1–2 teaspoons) for a full 10-liter watering can. Water the soil around the plants (not the leaves) with the mixture twice a month, and water fruit vegetables grown in greenhouses or tunnels, such as tomatoes, weekly.
The concentrate will keep for about a year in a cool, dark place. You can also infuse the eggshells with vinegar again and let them stand for two weeks. Then, add them to the compost bin.
Tip
Collect washed eggshells in a jar until you have enough.
