The next time you find yourself with freshly broken eggshells, perhaps after cooking a scrumptious omelet, don’t toss them in the trash! These tough casings can be washed, dried, and used as a supplementary source of nutrients for plants. Though eggshells are considered a type of waste with no actual economic value, their high calcium content makes them an ideal organic fertilizer for a wide range of crops, tropical plants, and flowering ornamentals.
While it’s near-impossible to come by enough eggshells to fertilize an entire farm of vegetables, a household’s weekly consumption of eggs should be enough to satisfy the needs of a few garden favorites. Eggshells contain calcium, phosphorus, magnesium, sodium, and potassium. They also have trace amounts of zinc, iron, and copper. These elements aid in various stages of plant development.
In plants, calcium is considered an essential nutrient. It is necessary for strengthening cell walls. It is also crucial for intra-cell communication, ensuring that important enzymes can be activated. While calcium deficiencies tend to be rare in nature, they may occur in horticultural and farm setups due to imbalanced mixtures or acidic conditions. The plants below should benefit from the nutrients of eggshells, producing higher-quality fruits in the process.
1) Tomato (Solanum lycopersicum)
Widely cultivated for its acidic juices, savory flavor, and versatile pulp, the tomato is definitely one of the world’s most beloved crops. Important to pizza and salad lovers alike, this species comes in hundreds of commercially important varieties. Many cultivars have been developed to be disease-resistant, but they all share the same need for a well-balanced formulation of essential nutrients.
In tomato production, calcium is necessary for the development of high-quality fruits. Optimal Ca concentrations in the substrate can increase the firmness of tomatoes. The strength of the fruit’s walls and internal tissues hinges on the availability of this macronutrient. Botanists have claimed that it can act like a natural glue for holding cells together.
Calcium, in a pre-formulated fertilizer, is often provided to industrially grown tomatoes. A lack of calcium can lead to blossom end rot, which damages the bottom parts of tomato fruits. A tomato patch in a home garden need not be treated with a store-bought, inorganic mixture to thrive. Instead, some of its most basic requirements can be provided by organic supplements like eggshells or compost.
2) Eggplant (Solanum melongena)
Aubergine, guinea squash, and brinjal are just a few common terms for the spongy fruits of this tender plant. Eggplants are basically elongated, purple berries that arise from the nodes of mature stems. The wild forms of these fruits or “culinary vegetables” rarely grow to more than 1 – 2 inches (2.5 – 5 cm) long. Those of their cultivars, in contrast, can measure as much as a foot long! Varieties found in the West tend to be more broad, whereas eastern eggplants are more narrow and long.
Some of the most common issues affecting cultivated eggplants, preventing them from growing to their full length or lasting for an acceptable time in storage, are associated with nutrient deficiencies. Calcium deficiency can lead to stunted growth, reduced yield, and the occurrence of blossom end rot (as with tomatoes). Eggplants require a lot of calcium, so supplements are usually necessary for favorable growth rates.
Calcium is often provided as a supplement in the form of limestone, Kelzyme fertilizer, or crushed oyster shells. A large number of crushed eggshells can easily match the beneficial effects of these store-bought supplements. Crushed, sterilized eggshells can be mixed into the substrate around patches of eggplants, or they can be introduced into the soil before eggplant seedlings are planted.
3) Broccoli (Brassica oleracea var. italica)
A cool-weather crop, this member of the cabbage family (Brassicaceae) is set apart by its deep-green and tree-like flower heads. Rich in important vitamins and minerals, it is often perceived as a bitter-tasting crop. It’s no surprise that many young children may take time to warm up to the strong taste and smell of broccoli. The flower heads contain glucosinolate compounds, which are pungent due to their richness in sulfur.
A hundred grams of raw broccoli tends to contain about 47 mg of calcium. This means that this crop must absorb a considerable amount of calcium from the substrate to thrive. Suboptimal concentrations of calcium begin to be manifested in young broccoli stalks, which may develop necrotic cells along the margins and tips of their leaves. Rotten leaves compromise the development and longevity of floral heads.
If you’ve begun to notice nutrient-deficient leaves, it may be high time to feed your plant with fertilizers or supplements. Take note, however, that excess potassium, sodium, or magnesium in the soil can affect the efficiency with which broccoli roots take up calcium. Using eggshells instead of pre-formulated mixtures ensures that calcium is provided without drastically increasing the concentrations of other elements.
4) Amaranth (Amaranthus spp.)
Amaranths are often cultivated as eye-catching ornamentals, leafy vegetables, or sources of cereal-like grains. They are distinguished by their vivid, catkin-like inflorescences, which boast an array of colors from purple-pink to deep-red. In spring to summer, the blooms of mature specimens can change the appearance of a garden, making it awash in texture and vibrance.
Some of the most commercially important members of Amaranthus include the pendant amaranth (A. caudatus), Prince-of-Wales feather (A. hypochondriacus), and red amaranth (A. cruentus). Though each of these can be cultivated as ornamentals, they are valuable due to their calcium-rich and starchy seeds. Their seeds are now considered a “superfood” as they tend to contain more calcium, protein, iron, and magnesium than other grains.
Given the large quantity of calcium in amaranth seeds, it’s no mystery why these plants require considerable amounts of calcium in the soil. To set your amaranth stands up to produce a bountiful display of blooms, incorporate crushed eggshells into the layers of topsoil around their roots.
5) Spinach (Spinacia oleracea)
Another fantastic source of calcium, spinach is lauded for being one of the most nutrient-rich leafy vegetables. This modest plant contains impressively high amounts of vitamins and essential nutrients. It expertly accumulates some of the most vital macronutrients in the soil and converts them into pharmacologically valuable compounds. Fortunately for us, it is relatively easy to cultivate, maintain, and harvest.
Though the typical N-P-K (nitrogen, phosphorus, potassium) fertilizers are favored for increasing soil fertility around crops like spinach, calcium is crucial as well. Spinach will grow poorly in calcium-poor substrates. Clear signs of deficiency include distorted leaves, stunted growth, and interveinal chlorosis (the development of yellow coloration in between veins that tend to remain green).
Spinach farms usually amend calcium-poor soils by adding lime or gypsum. If you intend to grow just a few patches of this species, eggshells are highly recommended. To improve the efficiency with which eggshells can benefit spinach, you can pulverize them and mix the powder into compost. The calcium-enriched compost may then be worked into the upper layers of the soil.
6) Chili peppers (Capsicum spp.)
Many gardeners are aware of the importance of a wide range of nutrients for chili pepper plants. Oftentimes, they’ll make use of all-purpose fertilizers, some of which have no traces of calcium or other beneficial minerals. Using an N-P-K fertilizer for Capsicum species in calcium-rich substrates should improve growth and yield rates. Its use in calcium-poor substrates, however, may do little to improve fruit production and quality.
Calcium affects cell development in pepper fruits in the same way it does with tomatoes. It is necessary for the development of sturdy cell walls, which reinforce the integrity of the overall fruit. It is also crucial for strengthening pepper stems. The presence of optimal Ca concentrations leads to the formation of dense root hairs, improving the root system’s capacity to take up more nutrients and moisture.
A study that looked into the use of eggshells as a fertilizer for cayenne pepper (C. frutescens) showed that it could significantly increase vegetative growth. This goes to show that the addition of organically-sourced calcium can definitely lead to healthier and more robust peppers. Gardeners of small-scale farms need not look far for a costless source of calcium!
7) Lettuce (Lactuca sativa)
Practically synonymous with “salad greens”, lettuce is a versatile, kitchen staple that can be grown in multiple ways. Nowadays, it is often intensively cultivated in vertical hydroponic gardens, allowing for the production of greater biomass within a small area. It remains to be a fun and easy herb to grow in the garden setting, where small-time gardeners can experiment with various growth conditions.
Nowadays, consumers have the liberty to choose between an immensely wide range of lettuce cultivars. Depending on the cultivar and the conditions in which they are grown, they may contain high or low concentrations of calcium in their leaves. Butterhead lettuce, a popular variety for salads and sandwiches, contains about 35 mg of calcium for every 100 g of leaves.
Eggshells are an ideal organic fertilizer for garden-grown lettuce because they can help balance the pH conditions of the soil. A well-balanced pH can make or break the quality of lettuce roots and leaves, affecting how well they can take up nutrients. Moreover, a moderate concentration of calcium from eggshells should help improve the crispness of the leaves and reduce the chances of tip burn.
8) Cucumber (Cucumis sativus)
There’s nothing quite like a cool and crisp slice of cucumber on a warm summer day. This phytonutrient-rich vegetable definitely deserves a spot in a tropical garden because it makes for a spontaneous treat! The fruit is borne on a creeping vine, one which effortlessly latches onto nearby plants and structures with its spiraling tendrils. A trellis, over which the large leaves can grow, is perfect for supporting its delicate stems.
Although 95% of the mass of cucumber is made up of water, it does require a fair amount of nutrients to thrive. In soilless media, cucumber roots would need to be provided with soluble calcium nitrate. Ideally, the roots should be situated in a mixture with a calcium concentration of about 150 – 200 ppm. Calcium deficiency in cucumbers manifests as puckered or seemingly scorched leaves, premature fruit development, or white spots on the surfaces of leaves.
Cucumber vines in the garden can be supplemented with calcium in several ways. You can simply crush clean eggshells and mix them into the soil or you can create an eggshell broth. Boil about a dozen eggshells in a gallon of water, and allow the mixture to steep over the course of a few hours. The calcium-infused liquid can then be used to water your cucumbers!
9) Strawberry (Fragaria x ananassa)
The modern strawberry plant is a hybrid between the wild strawberry (F. virginiana) and the Chilean strawberry (F. chiloensis). First produced in the late 1800s, it is now globally popular and highly desirable as a garden or greenhouse plant. Growing strawberries is undoubtedly rewarding for all gardeners, no matter how experienced they are. It’s amazing how this small plant can take in so many nutrients and convert them into compounds that make the sweetest fruits.
Strawberries can be described as calcium guzzlers. They require fairly large concentrations of this macronutrient to produce a desirable yield of fruits. The majority of the calcium molecules become stored and assimilated in the plant’s leaves, stems, and roots. Calcium-deficient specimens quickly develop crinkled leaves, some of which may have brown tips. They are also unable to produce adequately-sized fruits.
Eggshells are perfect for adding just the right amount of organically-sourced calcium to strawberry patches; young plants highly benefit from the supplementary calcium. Moreover, coarsely crushed eggshells can help prevent your strawberries from being attacked by snails and slugs. These leaf-eating critters are likely to stay away from the sharp edges. This goes to show that eggshells are genuinely multifunctional in the garden!
