Maybe you eat eggs daily, or you are raising backyard chickens for your own eggs- Either way, you are likely to come across an abundance of eggshells as kitchen waste.
Believe it or not, eggshells have been declared a Hazardous waste product by the European Union and are believed to contribute to around the same amount of waste in our oceans as plastics-‘Pretty surprising right!’
As a dedicated gardener, I’m sure one question that always comes to mind is are eggshells good for plants?
In this article, we will cover ways to lower your impact on the environment by using Eggshells in the garden whilst learning about the benefits they can bring to your plants.
In This Article
Eggshells and the environment
Eggshells are a common agricultural waste and have a large impact on the pollution to the environment. Not only do they take up a lot of space in landfill they also take a lot of time to degrade.
When you think about your household consumption of eggs per year and multiply that by the number of egg-eaters on this planet you can soon understand the quantity that is produced.
Their odor pollution and ability to attract microbial bacteria make this food waste a very serious environmental problem.
Another environmental factor to remember when disposing of your eggshells is that there are whopping seven million metric Tons of this lightweight problematic material waste produced every year.
What eggshells are made of
After reading about the problems they bring to the environment, you may wonder what eggshells are made of.
Most of the time when we are talking about eggshells, we are usually referring to chicken eggshells.
The eggshells consist of 34% Calcium Carbonate crystals, 0.3% magnesium, 0.004% Phosphorus and 0.3% Potassium. There is also 0.05% salt and 0.5% ozone.
With these minerals, it is no wonder that they make good fertilizer for your plants and add nutrients to your soil.
Now we know what they are made of, let’s have a look at their uses in the garden and how to prepare them for use.
Preparing eggshells to use in the garden
Before you start using eggshells in all the wonderful ways possible, it is important to prepare them first. The eggshells should be washed in warm water to remove any yolk or egg white from the inside of them.
After washing them place them on a paper towel to dry out for two days. The shell can also be cooked or baked in the oven for sterilization. You can store your crushed or powdered eggshells in a mason jar when not in use.
The recommended oven temperature is 200 degrees and the eggshells can be cooked for 15 minutes to kill any bacteria. This will make the egg shells more brittle which will help if you are going to crush them later on.
The reason for the preparation is to kill bacteria that could potentially attract unwanted pests or animals. This is especially if the egg shells are added to your compost pile.
By cooking and washing the egg shells you are going to help speed up the decomposition time.
If you are making your eggshell liquid fertilizer then the boiling process will cover this step for you.
Now you have carefully prepared your eggshells to be used in the garden, you can have a look at how they are applied.
Salmonella contamination through the use of eggshells in the garden
Salmonella is a living bacterium that tends not to rot in a compost pile but thrives and multiplies. It occurs when the birds lay eggs or when the eggs have come in contact with bird droppings. This is more common with eggshells from backyard hens as opposed to store-bought eggs that have been washed and dried.
If the appropriate preparation methods are not carried out before using your eggshells in the garden you can potentially risk Salmonella contamination amongst your vegetable crop.
When we think about raw eggs and handling these products it can raise concerns about the contamination of Salmonella bacteria.
By using the same methods, you would if you were working with raw meat, you can handle the egg shells- using gloves and washing hands with hot water and soap after handling will prevent contamination.
If you have great concerns regarding the contamination of salmonella from your eggshells you can follow the preparation methods of baking them in the oven to kill the bacteria and sterilize them.
This method only takes around fifteen minutes and will dry out the sticky layer and kill the bacteria at hand eliminating the risk. It’s better to be safe when it comes to dealing with certain animal products as the effects could be highly dangerous.
Now that you have an understanding of how to prepare the eggshells before use, we can have a look into how eggshells are good for plants.
Using eggshells in the garden to improve soil
To understand if your soil is lacking nutrients and requires improvement, it is recommended to take a soil test. You can use a PH test kit (commonly found in gardening stores) to test for Calcium deficiency in your soil and to determine whether you will need to add extra minerals to your garden soil.
Adjusting the soil Ph level revolves around what plants you will grow and their requirements. For example, Blueberries require more acidic soil whereas Cucumbers prefer Alkaline soil- you can do your research on each plant to have a good understanding.
Egg shells contain a small amount of Calcium, Iron, and Zinc. Even though the egg shells are fabricated with a considerable amount of organic material they can take quite some time to break down and provide nutrients to the soil.
A way to speed up this process can be to make eggshell tea fertilizer by boiling the eggshells in water and draining them. This is creating an extraction of the minerals that will be carried into the water.
After you let the boiling water cool down, you can pour it over your plants and it will provide the necessary nutrients for the soil whilst leaving the organic matter behind.
Eggshells affecting the pH of the soil quality
You can test your soil acidity with a pH test kit- which you can find at most garden stores. If the soil is shown to be acidic, one way to reduce the acidity is by using crushed eggshells. The added calcium from the eggshells makes them an alkali material and will balance the soil pH level.
It is best to aim for a pH level of 6.0-7.0 for most gardens but certain varieties require a more acidic soil or a more alkaline soil. When you are aware of the pH level that your plant requires you can amend the soil to suit the variety.
Some studies have shown that the eggshells will stop affecting the pH Level once the pH of the soil has reached around 6.8. So it is not necessary to keep adding eggshells after you have reached this level. You can test your soil each year to monitor any changes.
Using eggshells in combination with coffee grounds can provide a helpful mulch solution, the mix of the two substances will protect the top of the soil ensuring less evaporation of water. Both are highly rich in nutrients for plants offering an organic alternative to commercial fertilizer.
If you have a large area to mulch it may take a long time to save the eggshells. If you live near an egg processing plant you can always ask them to save shells for you.
Another way to collect a large number of eggshells to use as mulch is by asking your neighbors to save theirs too- which helps in reducing environmental impacts further.
Composting eggshells
By composting eggshells directly into your compost pile, you are already reducing your contribution to land waste.
If your composter is a sealed container this will assist in the breakdown of the organic matter but can be foul smelling and unproductive compared to an aerobic composting method.
The organic materials of the shells allure bacteria that are vital for the decomposing process whilst the enzymes speed it up.
Crushed eggshells construct air pockets in the compost and cause the organic material to degrade whilst the improved aeration in the soil assists in retaining water and improving drainage.
Research has found that eggshells can take more than three years to fully break down. The outer shell layer can be found fully intact even after one year of being underground. The quickest way for them to break down is to crush or grind them before adding them to the compost heap.
In addition to directly composting eggshells, it is also safe to add them to a worm farm. The worms will break down the hard material and give back the nutrients to the compost heap.
When composting eggshells, it is important to follow preparation methods before adding them to your pile. Due to the temperature of the compost pile some bacteria such as Salmonella can thrive and continue to spread.
With thorough preparation, you can compost your eggshells in a way that breaks down quicker and with less risk of contamination.
Read on to see preparation methods and more information regarding Salmonella contamination
The use of eggshells isn’t limited to being good for plants just by using them to improve soil conditions, they have benefits when it comes to the maintenance of your plants too.
Ground eggshell powder in the garden as a natural plant fertilizer
Due to the Calcium carbonate content of eggshells which is a crucial mineral required for plant growth, powdered eggshells are an effective and inexpensive calcium supplement for your garden and indoor plants.
You can utilize ground eggshells on your indoor plants hanging baskets and planters to provide them with extra calcium, potassium, phosphorus, and magnesium.
As mentioned before, the egg shells also help aerate the soil which aids in the plant’s root growth.
To pulverize the egg shells, you can use a food processor, coffee grinder, or mortar and pestle. Crush them until you get a fine powder consistency. Before pulverizing or grinding your eggshells, ensure you have followed the preparation methods of washing and baking to sterilize them.
When you begin to pulverize or grind your eggshells it is suggested to wear a mask so you don’t breathe in any of the eggshell powder.
When you are transplanting your plant mix the fine powder you have made into the soil beforehand and it will provide the necessary benefits your plant will need for a healthy life.
You can also add the ground eggshell powder to the top of your plants so that over time the nutrients will absorb through the soil.
Using eggshell tea to water plants
You can create your own organic eggshell tea using the eggshells from your food waste. This is probably one of the most successful methods to extract calcium from eggshells and create an inexpensive fertilizer for your plants.
Start with collecting your eggshells over time and once you have a sufficient amount you can crush them using a coffee grinder or mortar and pestle. It is recommended to use a gallon of water for every 10- 20 egg shells.
Take the crushed shells and leave them to soak in boiling water overnight. The next day you can strain the soaking eggshells and pour the water directly on the plants.
This method will give you the best extraction of calcium from the egg shells and is best when done once a week.
If you want to be more resourceful with your eggshells and use water you can make sure that each time you are cooking boiled eggs, let the boiled water cool down and pour it directly over your plants.
Although this is a great method to use your eggshells from food waste it shouldn’t be relied upon for your plant’s only nutrient supplements.
Using eggshells to start seeds
Yes, that’s right- these little biodegradable cases can be used as a container to start seeds. After you have saved egg shells over time, using a hand trowel or spoon you can fill them with seed starting mix leaving a few millimeters between the soil and the edge of the shell.
It doesn’t matter if the eggshell halves are cracked unevenly as long as there is sufficient depth to fill with soil they will work as seed starters.
Once you have added the soil using your finger to create a small hole in the dirt to sow the seed. Now you can treat the eggshell seed starter exactly as you would with a pot and water them daily.
When the seedling has reached a couple of inches or has grown its second set of leaves, they are ready for transplanting to a larger environment. Take the eggshell and gently crush the sides making a few shards come loose- this is to make sure the roots of the plant can escape the eggshell structure and begin to grow in their new space.
The compact containers will provide enough space for the plant’s roots to form and their slightly porous material helps with drainage.
Because they take some time to biodegrade after the first year another option is to create some holes in the shell to make sure that the roots can continue to grow into the soil that is provided for them.
It is to be noted that eggshells are not the best recyclable material to use as a container to start seeds because of their slow degradable time frame.
Reusing an egg carton will break -down faster and are more ideal for this.
Which plants can I use Egg Shells on?
Vegetable plants such as Cauliflower, Broccoli, and Cabbage will benefit from using eggshells. Other fruiting plants from the Solanum family like Peppers, Tomatoes, and Eggplants also require extra calcium during fruiting.
The cucurbit family which consists of Cucumbers, Zucchini, and squashes requires calcium and other nutrients to thrive making them ideal candidates for eggshell use.
Other leafy varieties such as Swiss Chard, Spinach, and Lettuce will also benefit from the nutrients supplied by eggs shell too.
You can also use eggshells on Strawberries and Marigolds which are both susceptible to unwanted pests such as slugs and snails.
Paired with a regular watering regime the slow release of calcium from the eggshells to these plants will assist in the prevention of blossom end rot and ensure the plant has a healthy amount of nutrients throughout its growth cycle.
Using crushed Eggshells on potted plants
Another method of increasing the plant’s calcium level is to add a layer thick of crushed clean eggshells to the base of the plant’s pots. Follow the preparation methods mentioned in the article to ensure you have sterilized your eggshells before use.
Take the pot that you have decided to transplant into and cover the drain holes at the bottom of the pot with split eggshells to make sure the smaller pieces don’t fall into the bottom dish.
Add the soil on top of the eggshells as you would normally do. Place the root ball of your plant onto the soil and backfill the pot with extra potting soil. Once you have transplanted the potted plants you can add a thick layer of crushed eggshells to the top of the soil in the pot which will act like a mulch material and help to deter pests and weeds and reduce water evaporation. You can add eggshells to the top of your plant every two weeks to ensure they have a good supply of calcium
Adding eggshells to the bottom of the pot helps with drainage and Calcium feeding plants such as tomatoes can get a good supply of calcium directly to the roots. Make sure to water your plants regularly and keep an eye out for any signs of pests or diseases.
Can I use ground eggshells on Ornamental house plants?
The outdoor garden is not the only place you can reuse your eggshells- yes you can use them to add calcium to the soil of your house plants too. You can add them to your planters’, hanging baskets, or any other containers you use to grow plants indoors.
They will add a nutritional boost to the soil quality as they break down over time and help with drainage in the pot.
It is important to not rely on eggshell powder as the only method of nutrients in the soil as your plants are likely to require different nutrients at various stages of their life.
Depending on what variety of houseplants you grow will determine the requirements they need for a healthy life.
Aftercare of your plants is just as important as how you start their life and eggshells are good for plants when it comes to various problems you may encounter later on.
Eggshells vs Pests
After spending a lot of time and effort to create a beautiful garden whether it be for your edible produce or aesthetics, the last situation you would want to occur would be an attack of pests on your hard work.
Depending on your environmental location and what plants you are growing you can potentially encounter a variety of unwanted species that pose a threat to your plants. For example, Tomatoes often attract Aphids whereas cabbages will attract cutworms.
You can do some research into what pests you can identify and which plants they are likely to be attracted to. Once you are able to make the identification of the pest you will be a step closer to eradicating the problem.
The regularly used and wasted food scrap can be used as a pest deterrent and assist in controlling slugs in your garden too. By piling hard crushed eggshells as a collar around the base of your plant you can control the number of unwanted visitors!
One particular pest that can cause a lot of damage to your plants is the Cutworm. They are soft-bodied and are unable to move over the sharp edges of the eggshells. You will have great pleasure watching them make a detour away from your cabbages!
Most soft-bodied insects we see as garden pests such as slugs and snails cannot pass through an eggshell barrier so once you have piled the eggshells around the base of the stem you should see a reduction in the number of unwanted guests.
Using eggshells as pest control isn’t just limited to small insects any unwanted visitor to your garden that has soft feet like cats for example can be put off by the sharp edges the eggshell barrier provides. Research has also found that due to the odor -even a large-sized animal such as a deer can be kept away from your garden if eggshells are used.
Can eggshells prevent blossom end rot?
Blossom end rot can be a sign of calcium deficiency in the fruit. It can go unnoticed at first until you see the tell-tale signs. It is a frequent dilemma in a vegetable garden that contains fruiting plants and can reduce the yield that you will receive from your crops. It commonly occurs in Tomato plants, Squashes, eggplants, and peppers.
A sign of blossom end rot is often seen as yellow leaves followed by brown leathery rot developing on the blossom end of the fruit. Not only can it be a sign of low calcium levels in the soil but also an irregular watering regime.
When watering your vegetable garden to avoid blossom end rot make sure you are giving a sufficient amount. If you live in a drought area when growing tomatoes, you may need to water twice a day for example. The water intake from the soil carries the calcium to the plant.
If you have experience with blossom end rot on your fruits you will need to remove the affected fruit and treat the soil.
Often there is sufficient calcium present in the soil but the plant has developed the inability to carry it to the fruits.
Because the eggshells’ calcium is very slow releasing adding them directly to the garden soil after planting to prevent blossom end rot won’t necessarily help the situation.
You can choose to add eggshells to your garden soil before planting and then in time they will break down during the time the plant is growing whilst adding calcium to the soil. You can also follow the other methods how to add calcium to your soil.
Are eggshells good for plants?
To summarize everything up, here are some reasons you may want to use egg shells on your plants.
- Egg shells are a waste material we need to reduce to lower the impact on the environment.
- If properly prepared they can be safely used in the garden.
- They make a great soil amendment
- Adding eggshells to your garden can provide extra Calcium to your plants
- Egg shells can be used as a pest deterrent
- Egg shells are not the best container to start seeds- there are many other biodegradable options available
Frequently asked questions
Which plants can I use eggshells on?
Vegetable plants such as Cauliflower, Broccoli, and Cabbage, fruiting plants from the Solanum family like Peppers, Tomatoes, and Eggplants, and plants from the cucurbit family which consists of Cucumbers, Zucchini, and squashes
Can you put eggshells on potted plants?
Once you have transplanted the potted plants you can add a thick layer to the top of the soil in the pot which will act like mulch and deter weeds. This will also help with soil erosion and evaporation.
How do you apply eggshells to plants?
You can use various application methods such as – Powdered eggshells, Crushed eggshells, and eggshell water to use on your plants.
How can I use eggshells as fertilizer?
You can create your own liquid fertilizer by boiling the eggshells and leaving them to soak overnight. The next day you can strain the soaking eggshells and pour the water directly on the plants.
Can I add too many eggshells to my plants?
No, the calcium from the eggshells will stop affecting the soil pH once it has reached 6.8 so after that, you will be left with their organic matter which benefits aeration in the soil. Obviously, you wouldn’t want to use eggshells as a complete potting medium and it should be added to your potting soil by approximately 4-5 eggs per plant.
