Perlite stands out as one of the most prominent growing mediums for every garden—may it be for succulents, houseplants, outdoor plants, and hydroponics. One thing that I really like about perlite is its superior water holding capacity, which is key to having moist soil. But, are there other alternatives?
Generally, perlite alternatives that can perform comparably well are pumice, horticultural grit, poultry grit, sand, coarse vermiculite, gravel, clay pebbles, crushed shell, cactus mix with pea gravel, calcined clay, coco coir, wood chips, and rice hull. By contrast, fine vermiculite, horse manure, and paver’s sand are bad perlite substitutes.
Can you easily get these perlite alternatives? Are they readily available in your backyard or do you need to get them online? Let me keep the answers to these questions in my pocket for now. But don’t worry, I will give them to you later!
Both pumice and perlite are porous rocks formed during volcanic eruptions and so they have very comparable characteristics. Pumice also has a high water-retention capacity and large particle size making it an ideal growing medium. In some ways, pumice is even better than perlite, such as for growing succulents.
For an easier view, I have summarized the differences between pumice and perlite in the table below.
|Heavier (it does not float and is not carried away easily)||Lighter (it floats and can be carried by the wind)|
|Produces less dust||Dusty in nature|
|Contains minerals||Does not have minerals|
|Relatively expensive||Relatively cheap|
|Best for succulents||Best for houseplants|
Pumice packs like the one below are available on Amazon.
Horticultural grit is composed of small stones with sizes ranging from 2 to 4 mm. It works similarly to perlite in the sense that it also creates air pockets within the soil. These air holes provide oxygen to the plant roots while preventing root rot due to improved drainage.
One thing that I also like about this is the fact that it creates less dust. Since it is made out of quartzite stone which has a glassy appearance, it is also free of dusty lime—making it suitable for use on both indoor and outdoor plants.
Horticultural grits like the one below are available on Amazon.
Non-alkaline and non-soluble poultry grit, also called cherry stone, is used to replace perlite to take advantage of its coarse grains and aid in soil aeration and water retention. Poultry grits are made of granite which is pH neutral.
This product is primarily used as food for chickens as it helps digestion and provides necessary minerals for the hen’s eggshells. However, what makes it a suitable substitute for perlite is its coarse particle size.
Poultry grits like the one below are available on Amazon.
Coarse silica sand also possesses perlite-like properties such as pH neutrality, sterility, nutrient-free, and excellent drainage capacity. However, it is critical to use sand with a diameter of 1.5 to 2 mm. Another option is to mix sand with clay-rich soil to balance their muddy texture.
Sand, unlike perlite, does not deteriorate. In addition, while it briefly absorbs moisture, it does not hold it for a long time. This is particularly true for relatively coarse types of sand. This is the reason why 1.5-2 mm sand is preferred.
Warning: Refrain from using very fine sand, like those used for construction or those you see at beaches.
Moreover, please remember that sand is much denser than perlite, so if you are planning to use it for houseplants, it might not be the best option. It is better to use it for outdoor plants, mixed into the soil.
You can purchase sand on Amazon which is made for growing plants just like the ones below.
Vermiculite is a non-toxic and sterile growing medium for any garden plant. However, coarse vermiculite (6-8 mm in diameter) is preferred over the typical fine vermiculite available in grocery stores. This is because it has excellent water-retention and capillary action properties. It also has less tendency of being soggy as a medium.
If capillary action is a new term for you, let me use a real-life example to demonstrate this concept.
If you have ever noticed your drink being stuck inside your straw, you have already experienced the concept of capillary action. In a nutshell, it is the force that your drink uses as it fights gravity, which is supposed to pull it downwards.
This property is critical when growing plants because the longer water remains in the potting mix, the longer your plants have access to water.
With its capability of capillary action, it is possible to fully retain soil moisture just by applying water from above and/or below the roots.
What to do when your vermiculite becomes waterlogged?
The best thing to do is to mix it with other growing mediums that drain water well. For example, coco coir or peat moss. This will balance the water-holding capacity of your growing medium. You can use 75% coarse vermiculite and 25% coir for the best results.
This section may seem strange if you have had a bad experience with vermiculite. But don’t worry! Another section before the end follows to discuss a possible reason why your vermiculite experience was unsatisfactory.
Gravel and perlite are not only comparable in appearance but they serve similar functions in soil mixes. Both of them are porous rocks that retain moisture, promote soil aeration, and drain well. However, gravel is heavier than perlite which makes it durable and reusable.
When using gravel, I recommend using smaller gravel sizes to hold your plant better. It also works best when mixed together with soil, coir, or other growing mediums. You can use a 1:2 ratio of gravel and soil for best performance.
Explore other media options in our article about 12+ growing mediums.
Although you can get rocks everywhere, gravel stones like the one below are also available on Amazon.
Clay pebbles are round pieces of expanded clay that have high porosity, making them an excellent media aerator. Just like perlite, it is also pH neutral and can absorb its weight in water.
As a potting mix, clay pebbles work best with a ratio of 1:9 to garden soil or coco coir. If you are planning to use clay pebbles as a mix, choose those that are relatively smaller in size (3-4 mm) like the one below on Amazon.
Moreover, clay pebbles are more appropriate for hydroponic gardening in deep water culture (DWC) systems.
Learn more about this type of gardening in our article DWC and how it works.
Crushed shells, typically from oysters, are pellet-sized products that are also suitable alternatives for perlite. They are a well-known source of coral calcium which is also needed by plants. Considering this, they are fit for calcium-loving plants such as orchids, spider plants, and ivy plants.
Like poultry grit, it is also being used as a feed supplement for chickens to strengthen their eggshells. But this has also proven its worth in the garden as a good substitute for perlite!
Since crushed shells contain calcium, there is a possibility that they can adjust the pH of the growing soil conditions. This is the reason why it must be used specifically for calcium-loving plants.
Amazon offers cheap crushed shells like the one below.
Cactus mixes are available online and are typically used as a perlite alternative but with a combination of pea gravel. They are usually composed of 70% pumice and 30% garden soil, which balance out the air space in the growing medium.
To use this, I recommend putting pea gravel first to your pot halfway and then filling the rest with some cactus mix. This way, the pea gravel adds weight and holds the pot in place. This will be helpful if you are living near the coast, or any windy place.
Here is a cactus mix available on Amazon.
Amazon also offers a pea gravel pack like the one below.
Calcined clay, like Turface MVP, is usually used in athletics as a conditioner for baseball fields. This can also be used in gardening because the clay granules can absorb water. As a result of the balanced air and water pore space brought by its angular shape, it also improves soil drainage.
If you are looking for another option that offers the same work as clay pebbles, calcined clay is a cheaper option. You can get clay pebbles from 6 to 8 bucks per pound, while calcined clay starts at 4 dollars per pound!
Check my recommendation below on Amazon.
Coco coir is a simple growing medium that is ideal for gardening. Like perlite, it also has a high water-holding capacity and porosity, which are both necessary for healthy plant growth.
If you are a beginner in the gardening world, this may be the safest alternative for you! One of the things I like the most about coco coir is how straightforward it is to use.
Aside from that, coco coir’s characteristics are quite impressive. If I am the boss and coco coir wants to get into my company, I will absolutely hire coco coir! Silly metaphor, but I know you get the point!
Benefits for the Soil
Coco coir is neither too firm nor too loose, giving it the ability to retain a large amount of water and oxygen! It is light and porous, providing your plants with plenty of room for adequate air and water circulation. These promote optimal root structure.
Finally, because coco coir is made from coconut husks, it is an organic choice for growing medium! Thus, growing your own food in your kitchen can be done completely organically with coco coir—no synthetic fertilizers, no artificial ingredients!
A coco coir brick like the one below is an easy-to-use option as it works just like soil! I have been using them ever since I started my garden!
Other Comparable Products
Dried sphagnum moss and peat moss are two of the most comparable products that work the same as coco coir.
The major difference among the three is their pH. Dried sphagnum moss and coco coir are both pH neutral, while peat moss is very acidic. Thus, peat moss must be used for acid-loving plants such as magnolias and daffodils.
Below are the dried sphagnum moss and peat moss products I use which are available on Amazon.
One of the primary components of readily available potting soil mixes is wood chips. It is best to add them to potting mixes since it helps with drainage, prevent compaction, absorb moisture, and gradually release nutrients into the soil, depending on its size.
A huge advantage of using wood chips is the fact that you can just get them in nearby trees or even in wood shops. This makes this option a really cheap one!
On Amazon, you can actually get the one below just for about 5 bucks!
However, choosing to use wood chips also has a downside. Before using this in your garden, the shavings should be sterilized by boiling or dipping in food-grade hydrogen peroxide to avoid contamination in your potting mix.
Perlite can be replaced in soil mixes with parboiled rice hulls. They are natural and eco-friendly since they are considered agricultural wastes. Rice hulls are lightweight and aid in soil drainage, aeration, and compaction prevention. They are also rich in silicon content which is beneficial to plants.
What is the role of silicon in plants? Silicon-rich growing mediums aid in fighting stress such as drought, toxicity, and wilting. Thus, having a cheap source of silicon as rice hulls is a big win for your plants!
Pro-tip: When using rice hulls, it is a good idea to boil them before using them to ensure that they are clean and disease-free!
Why? Remember that rice hulls can also be a source of plant pathogens. Thus, if sanitation is not done, you are risking your plants harboring possible harmful microorganisms.
Since rice hulls are agricultural by-products, you can usually get them in nearby rice mills for a minimal cost or sometimes, even for free! However, it is also available on Amazon like the one below.
Perlite prices on Amazon range from 0.80 to 1.50 USD per pound. This makes coco coir and wood chips cheaper alternatives for perlite—all under 1 dollar.
|Perlite Alternative||Price per Pound (USD)|
|Coarse Silica Sand||1.00|
|Cactus Mix + Pea Gravel||5.68|
Conversely—as you can see in the table above—rice hull, clay pebbles, cactus and pea gravel mix, pumice, calcined clay, and horticultural grit are considerably expensive replacements for perlite.
Whereas, crushed shells, coarse silica sand, coarse vermiculite, poultry grit, and gravel are within the price range of perlite.
Like perlite, fine vermiculite may retain moisture well, but it may turn soggy over time and lead to waterlogged soil conditions. When this happens, it may facilitate the growth of harmful microorganisms such as fungi and bacteria.
If you have gone through other sources, you may notice that vermiculite is a common suggestion for perlite alternatives. But, for me, we need to be more specific.
There are two vermiculite types available in the market—fine and coarse. Most vermiculite bags you’ll see and get in stores are fine vermiculite. Due to its accessibility, a lot of garden newbies choose to buy it. But they inevitably get bad experiences from using it for their plants.
Fine vermiculite, when used as a growing medium, has more chances of turning soggy because of the tiny spaces in its structure. In this condition, it is difficult for water to be drained. This is the reason why I have recommended using coarse vermiculite above, and not just the ordinary vermiculite bags available in garden stores!
Horse manure is sometimes used in place of perlite because it improves soil aeration and water-holding capacity. However, issues on odor, microbiological hazards, and herbicide residues outweigh the advantages. Thus it is not recommended.
1. Undesirable Odor
The obvious issue with using manure is its foul smell when being watered—making it not suitable to replace perlite for indoor and even outdoor plants! You would not want a defined odor lingering through your garden, right?
2. Microbiological Hazards
Along with this issue, we need to acknowledge that it is also a farm by-product. Thus, it is also possible that it carries bacteria that may negatively affect your plants.
3. Herbicide Residues
While others still indulge in the idea of using horse manure because it is cheap, the herbicide residues present in it are real plant killers! Why? How can that happen?
Remember that horses are fed with grass. And most of the time, farmers use herbicides to get rid of these grasses. When the horses eat grasses, they only digest the organic material from them. With this, there is a huge chance that the herbicide residues are carried and excreted as manure.
Since herbicides are synthetic chemicals, they can adversely affect plants. Garden experts recommend not using horse manure for vegetable gardening, specifically tomatoes, peppers, and eggplants.
Some gardeners use paver’s sand because, like perlite, it has large grains. However, it hardens when watered due to a polymer additive that is supplemented for its main purpose as a leveling medium for brickwork.
This mistake is usually done when finding a growing medium for succulents. As time goes by, the large grains of paver’s sand can become compact and oily because of the additive—so beware!
When this happens, you are depriving your plant of more than 90% of the air space that they need! Although this is close to a compacted desert soil condition (but this time in a pot!), it is still not ideal, especially for gardening newbies.
Can I use styrofoam as a substitute for perlite?
Styrofoam can be used as a substitute for perlite because it also enhances air space within the soil and has a high water-holding capacity as well. However, it is not recommended by experts since it is a form of an environmental pollutant that neither degrades nor decomposes.
Is using biochar as a substitute for perlite worth it?
Biochar as a perlite substitute is controversial. Although biochar offers promising physico-chemical properties, it is still deemed unnecessary and impractical. Biochar is more appropriate for large-scale plantations and too expensive (30+) if done in home gardening. It is suggested to use cheaper sources of organic material such as peat mixes.
Can I use perlite as a plant substrate?
Perlite is used as a plant substrate since it is firm enough to hold plants in place. It is better to use in hydroponics because perlite does not provide any supplementary nutrients. In the hydroponic setup, nutrients are provided by the hydroponic solution and perlite only acts as an anchor to support plant growth.
Perlite can be substituted with pumice, horticultural grit, poultry grit, sand, coarse vermiculite, gravel, clay pebbles, crushed shell, cactus mix with pea gravel, calcined clay, coco coir, wood chips, and rice hull because of their ability to retain water, provide air spaces, and improve the soil structure and drainage.
The cheapest perlite costs less than a dollar per pound; whereas coco coir cost less than half that. These two are relatively cheaper than the other alternatives. Moreover, crushed shells, coarse silica sand, coarse vermiculite, poultry grit, and gravel are close to the price of perlite—making them reasonable substitutes.
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- “Beaches and Sand” by Seraphin, D et al. in University of Hawai’i
- “Effect of the type of sand on the fracture and mechanical properties of sand concrete” by Belhadj, B. et al in Advances in Concrete Construction
- “Material Data Safety Sheet” by Hoople, N. in University of California Davis
- “Organic Farming: Are Our Alternatives Actually Sustainable?” by Sterner, K. in Pomona College
- “Pine Wood Chips as an Alternative to Perlite: Cultural Parameters to Consider” by Owen, W. G.in North Carolina State University
- “Potting Media for Containers” by Reddick, L.L. in The University of Arizona
- “Soilless Growing Mediums” by Thakulla, D. et al. in Oklahoma State University