Container gardens are an excellent alternative to in-ground gardening, especially for those living in apartments or smaller homes. But potted plants can experience soil loss over time, either at the top or via the container’s drainage holes. So how do you keep soil from falling out of a pot?
Here are eight tips to keep soil from falling out of a pot:
- Leave 2 inches (5.08 cm) of space at the top of the pot.
- Pour gravel onto the soil surface.
- Install a styrofoam pot insert.
- Use a spray bottle to water potted plants.
- Use high-quality potting soil.
- Install a cotton sheet at the bottom of the pot.
- Put a coconut fiber sheet over the drainage holes.
- Place sponges at the bottom of the pot.
The rest of this article will explore these tips in detail and teach you everything you need to know about preventing soil loss in container gardens.
1. Leave 2 Inches (5 cm) of Space at the Top of the Pot
Overfilled containers are a mess waiting to happen. A slight nudge can cause the soil at the top of a pot to fall out, leaving your flooring or carpet covered in dirt.
Plant pots that are overfilled can also make a mess during the watering process, as potting soil that contains clay can expand when wet. This causes the soil to dribble over the side of a container, creating a muddy mess.
However, one of the best ways to prevent soil from falling out from the top of a container is to leave 2 inches (5 cm) of space between the soil surface and the lip of the pot.
You can use a ruler or measuring tape to ensure your container’s soil levels aren’t excessive—preferably before transferring a plant into that container.
Of course, this option may not be suitable for all container plants.
For example, tiny potted plants may not be able to get enough light if they’re 2 inches (5 cm) below the rim of their containers. And if you’re working with containers that are 2 to 8 inches in diameter (5 to 20 cm), you’ll want to leave about half an inch (1.3 cm) of space between the soil surface and the container lip.
To help the soil surface remain stable and inside the container, you can also consider adding a little gravel to the top of the container.
2. Pour Gravel Onto the Soil Surface
A little gravel can go a long way in preventing soil loss. Adding stone to fill the space between the soil surface and the container lip can prevent soil from falling out from the top of the pot.
And no matter what size container or plant you’re working with, there’s an appropriately-sized type of stone for you.
Choosing a Container-Appropriate Gravel
Selecting the best gravel for your potted plants starts with considering your container’s size. As you might expect, smaller gravel pieces are appropriate for small potted plants, while larger gravel pieces are suitable for larger container plants.
Never Pour Gravel Into the Bottom of a Plant Container
It’s crucial to note that you should never pour gravel into the bottom of a plant pot. Many gardeners believe that adding gravel to the bottom of a container will help prevent soil loss via the bottom drainage holes, which is somewhat accurate.
However, gravel can also cause water retention, potentially leading to root rot and other water-related plant diseases.
If you’re more of a visual learner, here’s an informative video by Epic Gardening to learn more about why it’s a bad idea to pour gravel at the bottom of a plant container:
3. Install a Styrofoam Pot Insert
If gravel doesn’t appeal to you, you can use a pot insert to stabilize potting soil and prevent it from falling out. But while you might be tempted to purchase pre-shaped styrofoam pot inserts or floral foam, these may not be safe to use.
Dangers of Using Styrofoam
Before investing in styrofoam pot inserts or circles, you’ll want to consider its potential disadvantages.
For example, like styrofoam in potting soil, styrofoam pot inserts can:
- Leach chemicals into the potting soil
- Be messy to work with
- Be harmful to the environment
Let’s take a moment to discuss these drawbacks in greater detail:
Styrofoam Is Often Full of Chemicals
Floral foam is made of microplastics. These can degrade and mix into your plant’s potting soil. These plastics are also rich in potentially harmful chemicals, including formaldehyde and barium sulfate.
Standard polystyrene styrofoam also contains a few problematic elements.
Styrene exposure has been linked to several potential health issues, including:
- Impaired memory
- Vision loss
If possible, you’ll want to use a biodegradable foam that’s free of potentially harmful chemicals and long-lasting microplastics.
Styrofoam Can Be Messy to Work With
Cutting into styrofoam to create container-friendly inserts can be messy. Most types of styrofoam shred easily, resulting in tiny particles of foam that litter the floor or stick to your clothing.
These bits can also pose a risk to the environment when used in outdoor containers. After all, the microplastics found in most floral foams can take hundreds of years to decompose.
Styrofoam Isn’t Environmentally-Friendly
The chemicals in styrofoam and floral foam can harm the environment. For example, these chemicals can leach into the soil, causing it to become infertile and polluted.
Furthermore, after it rains, these chemicals can sink into the subsoil layers, including the aquifer. From there, the chemicals can enter local groundwater sources, contributing to pollution in the local drinking water.
Alternatives to Floral Foam and Styrofoam
Fortunately, there are eco-friendly, biodegradable alternatives to floral and polystyrene foam.
Let’s explore these plant-friendly options:
Biodegradable Packing Peanuts
Eco-friendly packing peanuts are a fantastic solution to keep soil from falling out from the top of a container. And when eco-friendly packing peanuts get wet, they begin to degrade. Over time, they can form a semi-solid protective layer that helps prevent soil loss via the top of your container.
Compostable Paper Bowls
Paper bowls are a fantastic, biodegradable alternative to gravel and foam. Be sure to find the right-sized compostable bowls that fit securely into the top of your pot.
To use bowls to keep soil from falling out, you’ll want to:
- Use a pair of scissors to cut an opening in the bottom of the bowl.
- Make a single cut from the wider part of the bowl up to your previous cut.
- Pull the bowl open and turn it so its base is facing upward.
- Fit the bowl onto the top of your container, ensuring the plant stem doesn’t touch the sides of the bowl’s bottom.
4. Use a Spray Bottle to Water Potted Plants
Overwatering is the most common cause of soil loss through a container’s drainage holes. However, switching to a spray bottle may be one of the simplest ways to keep soil from falling out of a pot.
Using a spray bottle to water a container plant also tends to be far less messy. While watering cans can splash water into the soil, resulting in noticeable indentations and muddy splashback, a fine mist from a spray bottle won’t disturb the soil or cause a mess.
Also, a spray bottle ensures direct contact with a plant’s roots. On the other hand, when water splashes onto a plant’s stem and leaves, it can increase the risk of mold growth and fungus gnats. However, misting the soil around the plant stem reduces the risk of disease and pests.
Of course, changing your watering habits isn’t the only way to reduce soil loss. Using high-quality potting soil that compacts easily and encourages strong root growth can keep dirt from falling out of drainage holes.
5. Use High-Quality Potting Soil
If you’ve been using topsoil or garden soil for your container plants, you might want to change your methods. These soils aren’t designed for container use, so they may be more prone to escaping via the pot’s drainage holes.
Fortunately, there are several high-quality potting soils from which to choose, many of which can encourage strong root growth. And remember, when your plant’s root system is well-developed, it will naturally hold onto dirt, preventing soil loss.
High-quality potting soil should be explicitly designed for your plant’s environment (indoor/outdoor) and type (succulents, orchids, flowers). Organic potting soil rich in natural fertilizers like manure is also an excellent choice, as it tends to stick together better than loose topsoils.
And if you’re planting seedlings, you might need a backup option to keep soil from leaking out from the bottom of the pot. You can use an unbleached cotton sheet as a practical solution.
6. Install a Cotton Sheet at the Bottom of the Pot
A layer of cotton at the bottom of your pots and containers can help block soil while allowing water to pass through. However, not all cotton sheets are safe for container plants. For example, bleached cotton fabric can release chemicals into the soil, polluting it.
Fortunately, you can purchase chemical and bleach-free, all-natural cotton fabrics to prevent soil from falling out of your container’s drainage holes.
For the best results with a cotton sheet, you’ll want to:
- Cut your cotton fabric into a circle that’s slightly wider (between ½ and 2 inches or 1.27 to 5.08 cm) than the bottom of your container.
- Paint the edges of the fabric circle with non-toxic glue.
- Place the circle at the bottom of the empty container.
- Press the glue-covered edges against the inside of the pot.
- Wait for the glue to dry before filling the pot with soil.
Cotton fabric isn’t the only type of liner that can keep soil from draining out of the bottom of your pots. Coconut fiber is equally capable of reducing soil loss.
7. Put a Coconut Fiber Sheet Over the Drainage Holes
Coconut fiber is an all-natural material that’s commonly used to line pots. It’s slightly thicker than cotton fabric, making it a more durable (and potentially more effective) way to prevent soil loss.
Coconut fiber sheets usually are easy to cut, malleable, and comparatively stiff. They easily fit into the bottom of containers, but unlike cotton fabric, they tend to push against the sides of containers. Consequently, you don’t need glue to keep this material from folding in on itself.
To use coconut fiber in the bottom of your containers, you’ll only need to:
- Cut the coconut fiber sheet into a circle that’s slightly wider than the width of your container’s bottom.
- Press the fiber circle into the bottom of your container.
However, you’ll still need to be cautious when covering this fiber with potting soil, as some soil may trickle into the gap between the coconut fiber and the pot. Therefore, you might want to use sponges for more secure and direct coverage.
8. Place Sponges at the Bottom of the Pot
If you’re looking for a slightly easier way to cover the drainage holes at the bottom of your container, you may want to consider using sponges. After all, sponges can prevent soil from falling out, but they allow moisture to seep out.
While you can use a standard unused dish sponge to cover the drainage holes at the bottom of your containers, it’s best to use all-natural, plant-based sponges instead. These are free of dyes, soaps, and harsh chemicals, making them an excellent choice for plant pots.
Soil can fall out of a pot when it’s overfilled, and it can also leak out via a container’s drainage holes. Soil loss is a common issue for those with container gardens, but it doesn’t need to be!
There are several ways to keep soil from falling out of a pot, including:
- Leaving space at the top of the container
- Pouring a few inches (5+ cm) of gravel onto the soil surface
- Installing a styrofoam insert
- Using a spray bottle to water plants
- Using high-quality potting soil
- Placing a cotton sheet at the bottom of the container