Whether you have moved into a new house or have started a garden project in your current yard, you may have stumbled upon seashells in the soil. If you live inland, this can be a quizzical occurrence leaving you wondering how they got there in the first place.
There are several reasons you may find seashells in your yard including weather occurrences like flooding and hurricanes, remnants of animal movements, or your yard may once have been below sea level. Some seashells are intentionally mixed with soil for healthier plant growing conditions.
Whatever the reason, it can be useful to know how those shells ended up in your yard or garden and how they can be beneficial to your plants.
Where You Live Influences the Likelihood of Finding Shells in Your Yard
If you live near a coast, the likelihood of finding shells in your yard is high, as strong winds blowing inwards towards the coast, can carry shells or shell fragments into your yard. There is also a greater chance that kids or other people collecting shells may be bringing them home as souvenirs from the beach.
Certain animals like snails can attach to larger animals and hitch a ride inland to places that one might not expect to find their shells, like in your yard. Larger animals may also deposit shells into your yard through their fecal matter.
If you live inland and find seashells in your yard, there is a high chance your geographic area was once located below sea level and is now home to a fossilized history of what it used to be. There is also a chance that large weather events like hurricanes and tropical storms carried sand and seashells inland.
8 Reasons Why You Might Find Seashells in Your Yard
1. Storm Flood
If you live in an area that is prone to flooding or is located below sea level where the chances of flooding are higher, these strong surges of water are likely to carry sand, shell, and other sea sediments with it, depositing them where the water settles.
2. Hurricanes and Strong Winds
In the same way water from floods can carry seashells inland, strong winds and large storms like hurricanes can also pick up seashells and other sediments from the beach and deposit them into your yard.
3. Your Yard Was Once Below Sea Level
If the geographic land you are on was once located below sea level, and you find shells and other fossilized fragments that do not make sense for the current climate of your area, you may have stumbled on to a bit of history.
Finding shells and other biological remnants from when your land was below sea level can be a window into the creatures and organisms that once existed in your space.
4. Your Yard Was Once Under Fresh Water
While some shellfish prefer saltwater, some varieties live in freshwater. If you are located away from a salty ocean and are wondering how shells ended up in your yard, it is worth knowing that shellfish and other seabed fragments can exist in freshwater. If your land was once under freshwater, this could be one possible explanation.
5. Seashells Can Be Found in Fill Sand
Since sand is made of the skeletons of coral and other sea life, there are likely seashell fragments found in fill sand used to stabilize structures in your yard and around your home. Fill sand is known to compact well and allow for the drainage of water.
It is found in landscaping areas that use paving stones or where water may be present to provide some semblance of structural stability to the surrounding area with strong visual appeal. If you or any previous owners of your home have used fill sand in your yard, there may have been larger shell fragments present that separated from the rest of the sand over time.
6. Previous Owners Used Seashells in Their Garden
Some people intentionally place seashells into their gardens to nourish their plants and keep pests away. Most seashells contain calcium and magnesium which can assist your plants in growing larger and stronger.
Seashells also contain a substance called chitin, which is a contained, slow-release form of nitrogen that plants need. Using shells and shell fragments can be an eco-friendlier option as water-soluble nitrogen solutions can leach into water systems whereas nitrogen released from seashells will not.
Previous owners may have also used seashells as decoration in their landscaping which were left there and shifted over time.
7. Animals Dropped Seashells in Your Yard
In some instances, seashells end up in unlikely places due to animal movements. Seagulls and other birds carrying shellfish for their food may drop them midflight into your yard.
Certain other creatures with shells (like snails and other gastropods) can hitch a ride on larger animals like tortoises and other land animals. Shells may also be found in the remnants of animal droppings from animals that were just passing through.
8. Your Yard is Over and Old Midden
As another window into history, the shells you find may be the signs that your land is located over an old midden. Shell middens are considered cultural spaces located in some mainland and coastal areas that were inhabited by indigenous peoples over centuries.
Some archaeologists believe that shell middens signified land markers, seasonal food gatherings, or waste from long periods of occupation in these areas. Middens are usually composed of seeds, animal bones, and shells. As these middens erode, the most visible element is the shells which could be what you have found in your yard.
Will Seashells Cause Any Issues to Your Yard?
Seashells can provide many benefits to the health of your garden and yard if tilled into your soil or mixed into your compost well. If you find or use fresh seashells in your yard, be careful not to leave them on the surface of your yard as this can attract birds and other animals who will likely move the shells or drop them in other unwanted areas.
If the soil in your yard already has a high pH, then the addition of seashells (which are high in magnesium and calcium) may make the soil too basic for plants to grow. Seashells create thriving conditions for plants where the soil’s acidity may need to be balanced.
Do Crushed Seashells Help with Pest Control in Your Yard?
Crushed seashells can benefit the health of your garden and yard in many ways. The calcium found in seashells can increase the pH of soil that might be too acidic for plants to thrive in. Seashell fragments allow for better water drainage around the roots of your plants which can help prevent rotting. The presence of chitin also has many beneficial effects on the health of your yard.
Chitin attracts chitin-devouring bacteria and fungi. Once the shells have decomposed, these bacteria and fungi go on to devour pests like root-knot nematodes. In this way, seashells provide the conditions for your plants to grow healthier and stronger which in turn makes them more resistant to pest attacks and other diseases.
How Can I Remove Seashells from my Yard?
If you have found whole or large fragments of shells in your yard that were brought in by humans or other animals, they can easily be picked up by hand or with a garden shovel and disposed of. This is ideal if the pH of your soil is already high and the presence of calcium and magnesium from these shells could create imbalanced growing conditions for plants.
In most cases, seashells are beneficial for your yard and over time they will naturally break down into small bits and completely decompose. If you prefer not to see shells in your yard, ensure they are mixed or tilled well into your soil so your garden gets the benefits while creating the optimal condition for them to break down.
If you are located over an old midden or if your land was once submerged below sea level, it can be nearly impossible to get rid of all the seashells present as they are a part of the dirt that makes up your geographic area.
It can be odd to stumble upon seashells in your yard or garden if you were not expecting them to be there. Whatever the reason they ended up there, seashells oftentimes provide nutrients that are helpful to your yard and garden. They also make quaint decorations in landscaping and are viewed as good omens in some superstition so they may be worth hanging on to.
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.