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.
Eggplant, peppers, broccoli, cauliflower and leafy greens, to name a few. But don't go overboard. Since it takes a while for the shells to decompose, Uyterhoeven recommends applying eggshell fertilizer to your garden or indoor plants just twice a year—in the fall and spring.
One final note: Make sure your soils aren't already alkaline before you add anything to up the pH; and never ever use eggshells or other pH-raisers around acid-loving plants like azaleas and rhododendrons.
Boil a gallon of water and add ten to twenty clean, dry eggshells. Let the shells sit in the water overnight, then strain them out. Pour two cups of liquid onto each plant. Repeat the eggshell tea process every two weeks.
Eggshell Benefits
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.
Epsom Salt for Plants
Aside from the anecdotal evidence about human benefits, Epsom salt does seem to help plants. Generations of gardeners have said it helps their plants grow bushier, produce more flowers and have better color. It's also said to help seeds germinate and repel slugs and other garden pests.
To prep the eggshells, grind with a mixer, grinder, or mortar and pestle and till them into the soil. 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.
Crush the clean eggshells, and pour boiling water over them. Let this soak overnight, and strain the shells out the next day. Pour the eggshell water right onto the soil. Your homemade all-natural plant fertilizer does not need to be kept in the refrigerator.
In most cases, the grounds are too acidic to be used directly on soil, even for acid-loving plants like blueberries, azaleas and hollies. Coffee grounds inhibit the growth of some plants, including geranium, asparagus fern, Chinese mustard and Italian ryegrass.
Eggshells take a lot longer to break down compared to many other compostable goods, and too many of them can increase the acidity of your compost. This shouldn't be a problem, unless you plan on using it to grow plants that prefer low soil pH.
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.
Slugs, snails, and cutworms can do severe damage to your garden. Protect your plants from these pests by spreading coarsely crushed eggshells around your garden. The jagged edges work much like Diatomaceous earth by cutting and then dehydrating these common garden pests.
Because eggshells are so versatile, you can use them as pest control as well as nutrition for your plants, be it for growing tomatoes or making compost.
Start saving your egg shells from breakfast. Halve them and make sure you rinse them out thoroughly. Using a small needle, make a small hole in the base of each egg shell for drainage. Using a teaspoon, add seed compost to the egg shell.
You can water your plants with banana peel water fertilizer once a week. Many plants require watering once a week, so you can use compost tea during each hydration session. However, if your plants need a drink more often in the summer, stick to only using banana water once a week.
Epsom salt can improve the blooms of flowering and green shrubs, especially evergreens, azaleas and rhododendrons. Work in one tablespoon of Ultra Epsom Salt per nine square feet of bush into the soil, over the root zone, which allows the shrubs to absorb the nutritional benefits.
Banana peels can be placed directly onto pot plant soil, or around the base of your garden as mulch. As they decompose, they will release nutrients into the soil to feed plants. If using banana peels in your garden, place a single layer straight on top of the soil, being sure not to let them touch the plant stem.
While plants need nitrogen (remember the NPK on fertilizers), too much nitrogen will create lots of green leaves but few berries or fruits. This means potassium-rich banana peels are excellent for plants like tomatoes, peppers or flowers. Banana peels also contain calcium, which prevents blossom end rot in tomatoes.
Crush the eggshells or grind them into a fine powder.
It is possible to use whole eggshells in your soil, but they will decompose much faster if they are crushed or ground into powder. To make the crushing process easier, bake the eggshells at 350 degrees until the start to lightly brown before grinding.
If you soak this egg shell in vinegar (which is about 4% acetic acid), you start a chemical reaction that dissolves the calcium carbonate shell. The acetic acid reacts with the calcium carbonate in the egg shell and releases carbon dioxide gas that you see as bubbles on the shell.
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.