Succulents are plants adapted to dry environments, naturally attracting gardeners seeking low-maintenance options. Gardeners often consider using kitchen scraps like eggshells to recycle organic material while providing the best environment for their plants. Whether these drought-tolerant plants benefit from the addition of eggshells depends on understanding the shells’ composition and the unique requirements of succulent soil.
What Eggshells Provide
Eggshells are primarily composed of calcium carbonate, making up about 95% of their dry weight. This compound is known as lime in gardening and is frequently used to alter soil chemistry. Eggshells also contain trace amounts of beneficial minerals, including magnesium, phosphorus, and potassium. Traditional gardeners often incorporate eggshells into the soil for vegetable gardens to supply calcium, which helps prevent conditions like blossom end rot. The calcium carbonate acts as a slow-release liming agent, raising the soil’s pH level over time.
Succulents’ Specific Soil Requirements
Succulents thrive in conditions that mimic their native arid habitats, requiring highly specialized soil. The most important requirement is rapid drainage and high porosity to prevent water from sitting near the roots, as poor drainage is the leading cause of root rot. The ideal soil environment for most succulents is slightly acidic to neutral, generally falling within a pH range of 5.5 to 7.0. This slightly acidic condition is necessary for roots to efficiently absorb essential micronutrients. Since calcium carbonate is alkaline, its presence buffers the soil and raises the pH, potentially making the soil too alkaline, which can lock up nutrients and cause deficiencies.
The Practical Reality of Using Eggshells
The calcium carbonate in eggshells is a highly stable compound, essentially a form of rock. When simply crushed and mixed into the soil, this material breaks down extremely slowly, often taking several years to fully dissolve and release its nutrients. This slow process means the shells provide very little immediate nutritional benefit to the plant.
Furthermore, unless the shells are ground into a very fine powder, their fragments do not contribute to the soil’s structure in a way that promotes drainage. Instead, they can impede water flow and create small pockets that remain wet, which causes root problems in succulents. For the shells to have any minor effect, they must first be sterilized and then pulverized to a flour-like consistency before being integrated into the potting mix. Even then, the risk of shifting the soil pH toward alkalinity remains a concern.
Better Soil Amendments for Succulents
Instead of relying on eggshells, focus on amendments that guarantee the necessary drainage and aeration for succulent health. Mineral-based additions are superior because they create space for oxygen and water to pass through quickly without decaying or compacting the soil. These materials are chemically inert, meaning they do not significantly affect the soil’s pH balance. Pumice, perlite, and coarse horticultural sand are the preferred amendments for creating a functional succulent mix. Mixing these grit materials with low-organic potting soil ensures the roots receive the rapid drying cycle they need to flourish.