Eggshells are a common piece of kitchen waste. Did you know that you can use eggshells in garden soil?
Prepared and used correctly eggshells can have a range of benefits from enriching the soil to boosting growth and even feeding the birds. During the course of this article we will not only look at how to best use eggshells in the garden, we will also explain how to correctly prepare and store the shells.
Rich in calcium, shells can be used to benefit your plants.
Why are Eggshells Beneficial?
The eggshell is a rich source of calcium.
The shell is largely made of calcium carbonate. This is the carbonic salt of calcium. Calcium is an essential garden soil nutrient that helps to nourish plant life.
Calcium benefits plants by helping them to grow and build healthy cell walls. If the soil is lacking in calcium new plant tissue, in particular shoot tips and young leaves can become deformed.
Calcium is also important for the activation of particular enzymes that coordinate cellular activity.
Plants lacking in calcium are also more prone to issues such as blossom end rot.
A number of plants are sensitive to calcium deficiencies in the soil. These include:
Calcium deficiencies can cause light brown spots to appear on the leaves and stems of plants. Instead of being lean and green new shoots become wrinkled. It may also deter flowering.
Be careful when using shells to boost calcium levels in the soil. The shells also contain sodium. This is released as the shells break down. Too much sodium in the soil can harm the plants.
A shell is a good, natural source of calcium.
How to Prepare Eggshells
Before using eggshells in the garden, they need to be prepared correctly.
While diseases such as salmonella are unlikely to develop, cleaning the shells before using them reduces the risk even further. Unless you are placing the shells directly on a compost pile, you should always clean and dry them before use.
To clean, simply wash the shells out and place them on a sunny windowsill to dry.
You can also clean the shells by sterilizing them. This can be done by baking the shells in the oven at 200 ℉ or 93 ℃ for 30 minutes.
Once cleaned, pulverize the shells with a pestle and mortar or coffee bean grinder. The crushed pieces can be stored in an airtight container until you are ready to use them.
Clean the shells before using them.
Adding Shells to Compost
One of the most effective ways to use eggshells in the garden is to place the shells in your compost pile.
Adding eggshells to your home compost pile helps to raise calcium levels. As we have already noted, calcium is a beneficial nutrient for growing plants. It helps to speed up growth rates, strengthen cell walls and makes nightshade plants more resistant to issues such as blossom end rot.
While shells break down fairly quickly, crushing them before adding to the compost pile or using a compost grinder can further speed up the process.
Make sure that you properly clean and dry the shells before adding them to the compost pile. This helps to get rid of the eggy smell that may attract unwanted pests to your garden.
You can also add the crushed shell pieces to a worm compost bin or vermicompost system. Here they can be useful in helping to maintain the correct pH level.
Using Shells to Amend Soil Levels
While some plants tolerate a range of soil types, others need a certain type of soil to grow. Most members of the legume family, including Black-Eyed Pea plants and Bush Beans, struggle in acidic soils. Others, such as Magnolias and Camellias thrive in an acidic soil.
If you are unsure, before planting use a soil test kit to discover the makeup and pH level of your soil. This knowledge enables you to make any necessary amendments before planting. Knowing and being able to change the pH level of your soil enables you to grow a wider range of plants.
Legumes struggle in acidic soil.
One of the quickest ways to lower the acidity level of your soil is to work crushed eggshells into the garden soil. As well as helping to lower acidity levels, this also helps to aerate the soil.
However, for this method to be effective you need a lot of shells. As a rule of thumb you need to grind around 150 shells to make one cup of powder. Lime, either on its own or combined with ground shells, can also be used to lower soil acidity levels.
Be careful not to lower the acidity level too much. Plants growing in overly alkaline soils can suffer from iron, zinc and manganese deficiencies.
Eggshells Create an Effective, Attractive Mulch
Mulch can have a range of benefits in the garden.
When used effectively mulch helps to keep the soil cool and deter weed growth. During the winter a thick layer of mulch keeps the roots of plants warm and protected during cold, frosty spells. An organic mulch also slowly breaks down overtime, giving your growing plants an extra nutritional boost.
You can use eggshells in the garden to create a cheap mulch. Simply clean and crush the shells before spreading them evenly over the soil.
Again, you need a lot of shells to cover a large area of soil. You can mix the shells with other common garden mulches such as bark to boost the amount of mulch you have. You can also combine them with oyster shells.
When used as a bark, the fine white texture of the eggshells adds visual interest and texture to the garden.
Enriching Homemade Fertilizer
As we have already noted, using eggshells in the garden is a good source of calcium for the soil and plants. One of the easiest ways to boost your garden is to add the cleaned shells to a homemade liquid fertilizer.
Combining the crushed shells with other organic materials such as coffee grounds and compost can create an effective fertilizer. It also helps to reduce your kitchen waste.
One of the easiest ways to turn the eggshells into an effective garden fertilizer is to make calcium water. To do this, steep your shells in water. After a couple of days strain the infused solution. This can then be poured directly onto your garden soil or plants. Calcium water solutions are also safe to use on houseplants.
If one of your houseplants that you haven’t repotted in a while, or is too big to repot, starts to look a little tired, try giving it a drink of calcium water. This can quickly help to revive tired plants.
Using Eggshells to Improve Your Soil
If you don’t want to go to the trouble of making your own fertilizer, you can simply work the cleaned, crushed eggshells into your garden or raised bed soil.
Used in this way, the shells can help to raise calcium levels in the soil. This, in turn, helps plants to grow strong and healthy. Raising calcium levels around members of the nightshade family in particular can help to prevent blossom end rot.
Plants that can benefit from this include:
Warning, blossom end rot can occur even if your soil contains a healthy amount of calcium.
Other causes of the disease include a lack of nitrogen in the soil and an incorrect watering routine. However, using eggshells in the garden to boost calcium levels can make your plants healthier by strengthening their cell walls. This makes them better able to resist disease.
Adding the crushed shells to the soil when planting can boost tomato plant productivity.
Large pieces of shell take a long time to break down. If you want your shells to have a more immediate impact on the garden, grind them up finely first.
Till the shells into the soil in the fall. This gives them time to break down before you plant the following spring. During spring planting you can add a second dose of crushed shells either in a fertilizer, calcium water or mulch for an additional nutrient boost.
One of the most effective ways to use eggshells in the garden is during planting. After digging a hole in the soil, sprinkle a handful of finely ground shells into the hole before planting as normal. This gives the roots quick and easy access to a plentiful source of calcium.
You can continue to support your plant’s growth by sprinkling a handful of shells around the base of the plant every two weeks.
If you are planting in pots, work the eggshells into the potting soil as you fill the pot.
Deterring Garden Pests
Many people like to use crushed eggshells in the garden to deter destructive pests.
Spreading crushed shells over the soil is thought to deter a range of soft bodied pests. As they crawl over the shells, the jagged edges cut the bodies causing the pests to slowly dehydrate and die. Pests that can be deterred in this way include:
- Japanese beetles.
In truth, I have had mixed success with this method. However, it doesn’t do any harm to your garden. As we have seen above, eggshells can benefit the garden in a number of ways, so feel free to try it in your garden.
Cats are averse to eggshells. Simply scatter on the soil or ground of areas that cats frequent. After treading on the shells a few times they soon decide to go somewhere else.
Crushed shells are also believed to deter deer. This is because deer dislike the smell of eggs. Scattering uncleaned shells around plants can protect them from deer. However, some smaller rodents love the small and may be attracted to your garden. Properly cleaning the shells to get rid of the smell before using them also helps.
Starting Seeds in Shells
If you don’t have any pots or Evanda Reusable Seed Starter Trays to hand, you can start seeds in eggshells.
To do this, use shell halves or slightly deeper. This extra space gives the fledgling roots some room to develop. Remember to sterilize the shells before using them.
Shells can be used to start seeds.
Before planting use a nail or pin to carefully make a small drainage hole in the bottom of the shell. This allows excess water to drain away, preventing issues such as seed drowning or root rot. Then, fill the shells with fresh potting soil and sow the seeds.
Aim to sow one seed per shell. It can be difficult to thin out clumps of seedlings without breaking the shells. After sowing, sprinkle the soil with water. Be careful not to flood the shell.
If you plan to use the shells to start seeds in, remember to also save your egg cartons. These are the perfect container to hold the shells in place as the seedlings develop.
When you are ready to transplant, either carefully remove the seed from the shell or transplant still in the shell. Like Jiffy Organic Seed Starting Biodegradable Pots, the shell breaks down as the roots spread, adding calcium to the soil.
It can take a long time for larger parts of the shell to break down. To help the roots spread, break away parts of the shell as you transplant.
You can also grow some herbs, such as cress in eggshells.
Shells can be used instead of plant pots.
Supplementing Chicken Feed
Calcium helps hens to lay thick shells. Adding crushed or powdered eggshells to chicken feed helps the birds to get the nutrients that they need.
You can supplement chicken feed with clean, crushed shells.
Don’t feed your chickens whole shells. Some people think that feeding chickens whole eggs can give them a taste for shells and lead to them eating their freshly laid eggs.
While there is no evidence for this, you still shouldn’t feed your hens whole shells. Large pieces of shell can get stuck in their throats and cause damage or choking.
Using Shells to Add Nutrients to Bird Seed
Similar to adding crushed shells to chicken feed, mixing crushed shells into bird feed helps to boost the amount of calcium wild or garden birds ingest. This can be particularly helpful for female birds just before and during the egg laying season.
Adding shells to bird seed can help wild birds to lay stronger eggs.
Remember to sterilize the shells before finely crushing them. Once prepared the shells can be mixed into a quality bird seed and added to your bird feeder.
In addition to providing a sustainable way to reduce kitchen waste, using eggshells in the garden can have a range of benefits. As we have seen above there are a number of ways that you can easily use eggshells in the garden to benefit your plants.
Jen is a master gardener, interior designer and home improvement expert. She has completed many home improvement, decor and remodeling projects with her family over the past 10 years on their 4,500 sf Victorian house. She is also a passionate farmer who keeps goats, chickens, turkeys cows and pigs on her farm, and an instructor for her community’s Organic and Sustainable Farming project.