Gardeners have been urged to stop spreading eggshells around their garden, as there’s a more efficient way to give plants the health boost that the food waste can provide.
Eggshells are regularly used in gardens to provide calcium to plants, which can help them grow and can even prevent diseases like blossom end rot in crops such as tomatoes.
Some gardeners add eggshells to their compost piles, but they can also be crushed and mixed directly into the soil around the base of plants. This method provides a “slow-release” source of calcium that can take several years to fully release.
According to one gardening expert, there is an easier hack to help give plants a calcium boost “instantly”.
You still need eggshells for the trick, so don’t go throwing them in the bin once you’ve had your breakfast, but instead of sprinkling them in your garden as they are, you’re going to use them to make a calcium-rich spray.
According to an agriculture and technology account on TikTok, crushing eggshells into a fine powder and sprinkling them into your soil isn’t the best way to use the food waste. They claimed the calcium in the shells won’t be available “for many years” because it’s “in the form of calcium carbonate” that breaks down very slowly in most soils.
To speed up the process, the experts suggest you should instead crush five or six eggshells into a “very fine powder” and place the powder into a clean glass or plastic container.
Next, squeeze in the juice of two lemons, or add in a couple of tablespoons of white vinegar. The mixture will begin to fizz immediately, which is the reaction of the acid starting to break down the calcium to make calcium citrate.
Calcium citrate is a “more soluble and plant available” form of calcium than the carbonate form that’s present in eggshells before they undergo this process.
The experts suggested: “Let this mixture sit and react for eight to 12 hours. After that time, drain it and dilute it into two or three litres of clean water.”
Once the mixture has been diluted, it’s then ready to be sprayed directly onto the base of your plants to give them a calcium boost that they can use “instantly”. You can also gently spray the mixture onto the leaves, but make sure not to do this in the middle of the day, as the heat from the sun could scorch your plants.
How to use eggshells in the garden
1. Soil amendment
Eggshells are rich in calcium carbonate, which helps balance soil acidity and provides calcium for plants.
- Rinse eggshells and let them dry.
- Crush them into small pieces or grind into a fine powder using a blender or mortar and pestle.
- Sprinkle the crushed shells or powder around the base of plants or mix into the soil.
2. Pest deterrent
Sharp eggshell pieces can deter soft-bodied pests like slugs and snails.
- Crush clean, dry eggshells into small, jagged pieces.
- Scatter them in a ring around plants you want to protect.
3. Seed starters
Eggshell halves make excellent biodegradable seed-starting pots.
- Carefully crack eggs and save the deeper half of each shell.
- Rinse and poke a small drainage hole in the bottom.
- Fill with potting soil and plant seeds.
- When seedlings are ready, plant the whole shell in the garden; the roots will break through as the shell decomposes.