What plants like eggshells?
How To Use Egg Shells In The Garden – Protect & Power Your Plants!
You might be amazed at just how many ways there are to use egg shells in your garden. And even more, how simple and easy it is to use them!
Not only can they help to power your plants, egg shells can also aid in protecting them from pests and soil deficiencies too. All while helping to build better soil quality by adding key nutrients as they break down over time.
Egg shells truly are one of the most useful and powerful organic materials around. For starters, they are filled with a slew of nutrients, with calcium being by far the most prominent. In fact, an egg shell’s makeup consists of nearly 95% calcium carbonate! And as you will see later in the article, calcium can be extremely useful in the garden.
In addition to all of that valuable calcium, the shells of eggs also contain trace elements of phosphorous, magnesium, potassium, zinc, iron and copper as well. All of which happen to play an important role in building and maintaining healthy soil – and in turn, growing healthy plants.
But the benefits go beyond simply improving soil health. Egg shells can also help in the fight against slugs and cutworms. Even more, they can aid in preventing blossom end rot on tomatoes and peppers too.
How To Use Egg Shells In The Garden
When you look below at all of the amazing uses for egg shells in the garden, it’s hard to ever imagine simply tossing away one into the garbage again. Especially when you can save and store them so easily all year long to have them ready when you need them.
For more on that, be sure to check out our article How To Save And Store Egg Shells Safely For Your Garden. But now – let’s take a look at how to use all of those egg shells to power your garden this year like never before!
Give Your Plants A Calcium Boost
When it comes to planting tomato, pepper, cucumber and other vegetable transplants in the spring, adding crushed egg shells to your planting holes can go a long way in powering your plants to new heights.
Calcium is a major component needed for growing healthy, vigorous vegetable plants. In fact, the lack of available calcium in the soil is the cause of one of the biggest issues tomato and even pepper growers face – blossom end rot.
When a plant cannot absorb enough calcium, the ends of young tomato and pepper fruit turn black and rot away. Unfortunately, many gardens face a lack of this all important mineral in their soil. Quite often, it is the direct result of growing the same vegetable type in the same space year after year.
At some point, without the mineral being replaced, there is simply not enough calcium left in the soil for plants to absorb for proper fruit development. When that lack of calcium nutrition occurs, blossom end rot is likely to follow.
But calcium plays an important role in more than just tomato and pepper plants. It is also a critical mineral that all vegetable plants need when it comes to developing their early cell structure.
Without enough calcium to absorb in the soil, young seedlings are unable to develop thick walls and strong roots. The result is a weaker plant with fewer blooms, and of course, a smaller harvest. But egg shells can help to solve that issue with ease!
Adding Crushed Egg Shells To Planting Holes – How To Use Egg Shells In The Garden
One of the best ways to help add calcium back into your soil is by adding egg shells to each of your planting holes. But how you add those egg shells can make all the difference in just how much calcium your plants can get. And even more, how quickly they get it!
Listen In Below To Our Podcast On How To Use Egg Shells & Coffee Grounds In The Garden
Egg shells can take a long time to break down in their natural state. But by pulverizing and crushing the shells into tiny bits, you speed up the ability of the shell to decompose and release its nutrients into the soil. The more quickly calcium gets in the soil, the faster it will get to your plants.
In short, when adding to planting holes, egg shells need to be broken down as finely as possible. And one of the best ways to completely pulverize them is with a small coffee grinder. It makes quick work of the task. Even better, it leaves you with a fine calcium boosting powder that absorbs into soil and plants quickly!
Always be sure to clean and sanitize any blades or instruments used for crushing up shells. This helps eliminate any possibility of passing on salmonella or other bacteria with any equipment.
So how much egg shell powder should you add to each planting hole? A good rule of thumb is to use four to six egg shells for each plant. When ground down to a near powder form, that works out to about two tablespoons of finely crushed shells per hole.
For best results, dig your planting hole and then mix in the ground shells as you add soil back in. Try to keep the crushed shells right around the root ball of the transplant. This will provide all of the nutrients right where the plant needs it most, at the root level.
Top Dressing Plants With Egg Shells – How To Use Egg Shells In The Garden
Another great way to provide power to your plants while they grow is top dressing them with additional crushed egg shells on the surface around each plant. Just as when putting egg shells in planting holes, the more finely ground the powder, the faster the nutrients will leach down to the roots.
For topical use, a good rule of thumb is to use about a tablespoon or two of pulverized egg shells per plant. By giving plants power both below and above, you double your chances for success. But as you will see in the next section, adding even a few more shells on top that aren’t quite as powdery can pay off for your plants too!
Protecting Plants Against Slug, Cutworm & Pest Damage – How To Use Egg Shells In The Garden
Egg shells can also help protect tender young plants in the garden from slugs cutworms and other pests. But in this case, you will want to slightly crush your shells instead of completely pulverizing them.
When lightly crushed and placed around the base of plants, the sharp, jagged edges of the shells form a protective barrier. A barrier that the smooth, slimy, outer skin of slugs, cutworms and other small pests can’t cross without being cut.
Even better, as the shells break down, they only serve to add more nutrients to the soil. For this reason, many gardeners use crushed shells around all of their plants, including potted plants as well.
In The Compost Pile – How To Use Egg Shells In The Garden
Finally, when not using your egg shells to power plants, repel insects, or prevent disease, they always have a home in the compost pile! Egg shells add all of the same important nutrients to your compost pile that they do when placing them in the soil.
Just as when using in and above planting holes in the garden, crushing shells before placing in your pile is a good practice. It not only helps the shells break down faster, but reduces any chance of odor and smell. It also can help to keep wandering animals from finding your pile and snacking on them.
One thing is for sure, there’s never a need for egg shells to find their way into a landfill. Not with all of the benefits they bring to a home garden! Here is to saving and using egg shells to help power your garden and plants this year.
This Is My Garden is a garden website created by gardeners, for gardeners. We publish two articles every week, 52 weeks a year. Sign up today to follow via email, or follow along on Facebook here : This Is My Garden. This article may contain affiliate links.
By Author TIMG
Posted on Last updated: January 4, 2023
Are Eggshells Good for Plants?
Discover the best method of adding eggshells to your garden soil.
- Wesleyan University, University of California, Berkeley
David Kuchta, Ph.D. has 10 years of experience in gardening and has read widely in environmental history and the energy transition. An environmental activist since the 1970s, he is also a historian, author, gardener, and educator.
Updated June 16, 2022
Fact checked by
- University of Tennessee
Elizabeth MacLennan is a fact checker and expert on climate change.
- Planting Guides
- Indoor Gardening
- Urban Farms
In This Article
Eggshells are a serious environmental problem—with an estimated seven million metric tons of eggshell waste produced every year. That’s roughly equivalent to the amount of plastic waste that annually ends up in our oceans. In a landfill, eggshells produce odor pollution and attract microbial growth, which is why the European Union has declared them a hazardous waste.
Keeping those eggshells out of the landfill by using them in your garden is thus a good thing. Indeed, using eggshells in your garden can improve soil quality and encourage plant growth. The question is how to use those shells.
While composting eggshells along with other food waste is wise, most other common tips exaggerate the benefits of using eggshells in the garden. In fact, directly adding eggshells to your garden has few proven benefits.
How Eggshells Impact Soil
Approximately one-third of the mass of eggshells is composed of calcium, and the rest is small amounts of magnesium, sodium, potassium, iron, zinc, and copper. While eggshells also contain a fair amount of organic matter (remainders of the yolk and albumen), the shells themselves are very slow to decompose and release their nutrients into your soil.
To speed up the shells’ decomposition, some garden sites suggest pulverizing the shells and adding them directly to the soil. Others suggest making “eggshell tea»—soaking the shells in boiling water overnight (to kill pathogens such as salmonella), then straining them the next day to create a liquid plant fertilizer.
But eggshells’ most important benefit is their mass, not their nutrients. You will get more benefits out of eggshells by adding them to your compost, not directly to your soil.
Compost Your Eggshells
In a compost pile, the shells’ organic matter attracts microorganisms necessary for the decomposition process, while their enzymes speed that process up. Broken (not pulverized) eggshells create air pockets in your compost, which also encourages the breakdown of organic matter.
Your compost will be ready to add to your soil long before the eggshells in it have completely broken down. That’s a good thing since the increased aeration from the shells create helps the soil retain water. The shells’ surface area also binds nutrients from other decaying organic matter, preventing them from leaching out of your soil and into the groundwater, beyond the reach of plant roots.
What Eggshells Can’t Do
Here are some common misconceptions about gardening with eggshells.
Prevent End Rot
End rot is often caused by a calcium deficiency in plants such as tomatoes, peppers, eggplants, and squashes. But given how slowly eggshells release their nutrients, adding them directly to your plants is unlikely to help. Most soil contains a suitable amount of calcium to prevent end rot. End rot is more likely caused by irregular watering, which reduces the plant’s uptake of calcium in the soil.
If you are unsure of your soil’s nutritional content, contact your local extension service to get a detailed soil analysis.
Transform Your Soil’s pH
Calcium carbonate is a good additive if you’re trying to make your soil less acidic. An eggshell compost can raise the soil pH and also reduce levels of lead and other heavy metals in your soil—when the eggshells are used on an industrial scale. You’ll need to add quite a bit of eggshells (such as from an egg-processing plant) to re-balance the pH of your soil. There are far easier (and cheaper) ways to reduce the acidity of your soil.
Control Slugs and Snails
A common assumption is that eggshells’ sharp edges act as a deterrent to garden pests such as slugs and snails. But a study by the Royal Horticultural Society found that crushed eggshells did not protect plants from damage inflicted by snails and slugs.
The thick slime that the pests produce acts as a protective shield, allowing them to slide right over sharp objects. If you have the stomach for it, you can find videos on YouTube of slugs and snails crawling over knife blades, razor blades, and other sharp edges.
Make Great Seed Starters
Sure, you can use eggshell halves to start seeds, but why bother? The seedlings will soon enough need to be transplanted into larger pots or into the garden, as their roots are not strong enough to penetrate the shell and breakthrough into the soil. If you want an inexpensive, repurposed seed-starting pot, try newspaper or recycled paper.
Better yet, the egg carton itself is a perfect seed starter, without the need to carefully break eggshells in half. When it’s time to transplant the seedlings, just cut the carton into individual cups and plant the seedlings directly into the garden. The cardboard will break down as the plants grow.
The Carbon Footprint of Eggs
If you really want to do right by the environment and still have a healthy garden, skip the eggs altogether. The carbon footprint of egg production is similar to other basic foods of animal production such as milk, primarily through the production of animal feed for egg-laying hens.
Even if you’re raising your own backyard chickens, switching to a (primarily) plant-based diet is not only more sustainable for the environment as a whole, but the food waste from those plants will break down more quickly and add a wider variety of nutrients to your garden soil.
Frequently Asked Questions
How do I keep salmonella bacteria out of my compost pile?
When adding eggshells to a compost pile, make sure that your compost pile reaches over 140-160 degrees F to kill salmonella bacteria.
Can I use eggshells to keep cats from using my garden as a litter box?
Sharp eggshells can deter neighborhood cats from digging around in your garden, but you’ll have to frequently refresh your supply of crushed shells, and the eggs’ decomposing organic matter may attract other pests instead.
View Article Sources
- Ye Feng, et al. “Preparation and Characterization of Polypropylene Carbonate Bio-Filler (Eggshell Powder) Composite Films.” International Journal of Polymer Analysis and Characterization, vol. 19, no. 7, 2014, pp. 637–647., doi:10.1080/1023666X.2014.953747
- Vandeginste, Veerle. “Food Waste Eggshell Valorization Through Development of New Composites: A Review.” Sustainable Materials and Technologies, vol. 29, 2021, pp. e00317., doi:10.1016/j.susmat.2021.e00317
- Silvano, Mgnardi, et al. “Valorization of Eggshell Biowaste for Sustainable Environmental Remediation.” Scientific Reports, vol. 10, no. 1, 2020, pp. 2436., doi:10.1038/s41598-020-59324-5
- Ajala, E. O., et al. “Characterization and Evaluation of Chicken Eggshell for Use as a Bio-Resource.” Arid Zone Journal of Engineering, Technology and Environment, vol. 14, no. 1, 2018, pp. 26–40.
- Voyle, Gretchen. «Blossom End Rot Causes and Cures in Garden Vegetables.» Michigan State University Extension, 2015.
- Perry, Ed. «Prevent Blossom-End Rot by Watering Deeply and Regularly.» The Stanislaus Sprout, 2021.
- Soares, Micaela, A.R. et al. “Immobilisation of Lead and Zinc in Contaminated Soil Using Compost Derived from Industrial Eggshell.” Journal of Environmental Management, vol. 164, 2015, pp. 137–145., doi:10.1016/j.jenvman.2015.08.042
- Jones, Hayley, et al. «Gastropod Barriers.» Royal Horticultural Society, 2018.
- Abín, Rocío, et al. “Environmental Assessment of Intensive Egg Production: A Spanish Case Study.” Journal of Cleaner Production, vol. 179, 2018, pp. 160–168., doi:10.1016/j.jclepro.2018.01.067
- Pelletier, Nathan, et al. “A Carbon Footprint Analysis of Egg Production and Processing Supply Chains in the Midwestern United States.” Journal of Cleaner Production, vol. 54, 2013, pp. 108–114., doi:10.1016/j.jclepro.2013.04.041
- Clawson, Beth. «Adding Egg Shells to Compost.» Michigan State University Extension, 2013.