Plants like tomatoes, peppers and eggplants in particular will benefit from shell fertilizer, Savio said. The extra calcium will help prevent blossom-end rot. Broccoli, cauliflower, Swiss chard, spinach and amaranth are also calcium-packed and could use extra from eggshells.
Don't add eggshell fertilizer to plants that prefer acidic soil, like blueberries. Ericaceous plants such as mountain laurel, pieris and azaleas also fall into that category.
While eggshells are compostable and can be added to your kitchen countertop bin or backyard compost pile, using eggshells for plants is also beneficial. They provide important minerals—namely calcium carbonate, potassium, and phosphorus—that can be absorbed by your plant's roots after breaking down.
The shell of a chicken egg is comprised of about 96% calcium carbonate (CaCO3). Calcium is an essential plant nutrient and moderates soil acidity. Fast-growing plants deplete the soil of calcium very quickly so egg shells are an ideal supplement and feed for outdoor flowers, vegetables and fruit trees in your garden.
Clean, dry eggshells can go directly into your compost, says Yvonne Savio, who worked as a master gardener coordinator for L.A. County and runs the website GardeningInLA.net. You also can put crumbled shells in the soil before you place plants or seeds.
It will also boost certain flowers (perennials and annuals), such as roses and chrysanthemums. Eggshell fertilizer is good for succulents, but it lacks nitrogen, which some succulents might require. On the other hand, the extra calcium in eggshell fertilizer will harm to certain outdoor and indoor plants.
It is not a requirement to wash eggshells before composting them, but you definitely need to. First, cleaning them speeds up how fast they will break down inside the composting bin. Secondly, cleaning them is important so as not to attract animal pests.
As it happens, eggshells can provide all the calcium carbonate the soil needs, which helps to lower the soil's pH level and make it more alkaline as opposed to acidic. This is incredibly beneficial for plant growth because many plants prefer to grow in soil that has low acidity.
Clean Eggshells are Safe Eggshells
Eggs are known carriers of salmonella, which should not be present on uncracked eggs that have been well washed, but you never know. Unless the only place the eggshells are going is into the compost bucket, I rinse them well and let them dry in a sunny windowsill.
Because it takes several months for eggshells to break down and be absorbed by a plant's roots, it is recommended that they be tilled into the soil in fall. More shells can be mixed into your soil in the spring.
Do eggshells in compost attract rats? Any food scraps can attract local pests, including eggshells. But shells do not give off a strong scent, so there's little risk of these bringing in rodents on their own.
Banana peels contain: calcium, which promotes root growth helps add oxygen to your soil. magnesium, which assists with photosynthesis. sulphur, which helps plants develop strong roots and repel pests.
Wondering what plants don't like eggshells? It's best to avoid using them on varieties that naturally prefer more acidic soil, such as azaleas and geraniums.
Just like in the garden, finely crushed eggshells provide an organic source of nutrition for houseplants, patio pots and hanging planters. Sprinkle the pulverized shells on the soil surface and they will break down over time whether you are using eggshells for houseplants or outdoor containers.
According to some widely circulating advice, they can be disinvited to the party by placing crushed eggshells around plants. The rationale is that crawling over the sharp edges will deter an invasion.
Eggshells ground to a fine powder yield the quickest results, while large chunks of eggshells will take at least a year to break down making their stored calcium plant available perhaps the next growing season.
In most cases, eggshells help improve the soil pH and increase or decrease it to a neutral level. For example, lavender does not enjoy acidic soil. If the soil in your region is acidic, mix eggshells in it to make the soil neutral and tolerable for the plant to grow properly.
Composting tea bags is an environmentally-friendly practice that all tea drinkers should consider incorporating in their daily routines. Tea is a natural, organic material that's rich in nutrients, and it's easy to add to a compost pile.
Eggshells serve double duty in a garden. If you mix them into the soil, they'll have the same impact that they do in your compost: they'll decompose and feed valuable nutrients into the soil, which in turn will make your plants happy.
You can simply add crushed eggshells in or on the soil as a natural way of providing your indoor plants with extra calcium. Another advantage is that the eggshells will also help to aerate the soil. Airy soil makes it easier for your plant's roots to grow.
Boost potted plants
When potting plants, place a few used tea bags on top of the drainage layer at the bottom of the planter before adding soil. The tea bags will help to retain water and will also leach some nutrients into the potting medium.
Primarily a rich source of calcium, eggshells help roses by strengthening the walls of the plant's cell tissue. When rose plant parts are at their sturdiest, they are better able to fight off disease and pests.
Jeff Gillman, Professor and author of several books including The Truth about Garden Remedies suggests using shells from 4 to 5 eggs per plant. Mix them in the garden soil or potting mix prior to planting. The water used to boil eggs could also be used as a liquid fertilizer for plants.