Plants like tomatoes, hydrangeas, eggplants, roses, cabbage, squash, and peppers will love the added calcium boost. However, you should avoid using eggshell fertilizer on acid-loving plants, like blueberries, azaleas, and geraniums, if you already have soil that is veering towards alkaline.
There are multiple plants that benefit from eggshells in your garden. Tomatoes, peppers, broccoli, spinach, lettuce, Swiss chard, flowers, strawberries and squash are some examples!
Most flowers will also benefit, as will many succulents (just don't overwater them). 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.
The advantage of using crushed eggshell is less energy needed for preparation, but the disadvantage relies on the time needed for eggshell degradation before it can provide nutrients for plants (Mitchell, 2005; Rai et al., 2014).
Using eggshells for fertiliser
For fertiliser, Craig suggests using a mortar and pestle for crushing and sprinkling crumbled shells directly into planting holes, which he says particularly benefits vegetables such as tomatoes and peppers, as well as roses and hydrangeas.
Are eggshells good for roses? Yes! Eggshells add nutrients, help stabilize the pH level and act as a natural deterrent against some pests. Snap a photo for instant plant ID, gaining quick insights on disease prevention, treatment, toxicity, care, uses, and symbolism, etc.
It's best to start adding coffee grounds to the soil months before the blooming season begins, ideally in the late fall. You can repeat the process with your typical fertilizing schedule. With a little caffeine and a lot of patience, your hydrangeas should reward your efforts come spring with the boldest blue globes.
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.
The reaction of the eggshell in vinegar is an acid-base reaction. When you submerge an egg in vinegar, the shell dissolves, leaving the inner semi-permeable membrane intact. Vinegar (acid) breaks apart the solid calcium carbonate crystals (base) in the eggshell into their calcium and carbonate parts.
Depending on the size of your garden, compile enough of each component to contribute a moderate amount to each hungry plant. Combine the two together, crush the eggshells by hand even more (which should be easier now that they're fully dry), and sprinkle the mixture across the soil bed.
Plants like tomatoes, hydrangeas, eggplants, roses, cabbage, squash, and peppers will love the added calcium boost. However, you should avoid using eggshell fertilizer on acid-loving plants, like blueberries, azaleas, and geraniums, if you already have soil that is veering towards alkaline.
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.
If you have the luxury of holding your Begonia medium before using, here are some ideas for adding a natural compost to your soil before you pot up, or add to your potted plants. Eggshells (crushed): provide calcium. Crush and sprinkle over potting media. Chicken bones (cooked, dried, crushed): provides calcium.
According to our friends at Delish, adding a teaspoon of baking soda to your boiling pot of water will help the shell peel off seamlessly. Why? The alkaline in the baking soda will help your egg whites loosen up from the shell, making it easier to peel.
It is advisable to crush and incorporate eggshells into your garden soil regularly, as they provide valuable calcium and minerals that benefit plant growth. Aim to scatter crushed eggshells around your garden every few weeks or as needed.
Lay shells evenly on a sheet pan. Bake at 400°F for 10 minutes to dry the shells. Transfer shells to a food processor and pulse until finely crushed. Spread a thin layer of eggshell powder around the roots of vulnerable garden plants (repeat after heavy rain).
The calcium in the shells will strengthen the tomato plants, give you more buds (aka: tomatoes!) and sometimes even prevent blossom end rot – that brown disease that sometimes makes the bottom of your tomatoes brown and yucky!!
You can put raw or cooked eggshells in compost, either washed or not, depending on how concerned you are about pests in your compost. You can put them in as is, but you will find that eggshells take a lot longer to break down in compost than other materials.
It is beneficial to use egg shells when growing your own vegetables like tomato, pepper and aubergine or plants such as roses, hydrangeas, spider plants, ferns and ivy. Another way to add this homemade fertiliser to your plants is through a calcium solution.
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.
Generally speaking, acidic soil, with a pH lower than 6.0, yields blue or lavender-blue hydrangea blooms. Alkaline soil, with a pH above 7.0, promotes pinks and reds. With a pH between 6 and 7, the blooms turn purple or bluish-pink. To lower your pH, add garden sulfur or aluminum sulfate to your soil.
A good, natural geranium fertiliser is coffee grounds, as these contain just the right mix of potassium, phosphorus and nitrogen to provide all the nutrients geraniums need for optimal growth. To ensure an even supply of nutrients, we recommend weekly applications of fertiliser.