If you have a deep-rooted love for potted plants and need the right potting soil mix, this might help.

If your plants are always unusually dry, malnourished, and slow to germinate, this might be something for you.

The impressive growing benefits of vermiculite is something you should find out more about.

You can use a vermiculite and peat mixture for germinating all your seeds and bulbs. The combination of soil and vermiculite can be the foundation for all of your houseplants.

What is Vermiculite?

Vermiculite is an all-natural mineral that is used as both a building material and a planting medium. Its scientific name is hydrated laminar magnesium-aluminum-iron silicate.

In its natural form, vermiculite is flaky and metallic, much like mica. However, when it is heated at a very high temperature, it puffs up. Vermiculite’s ability to expand, or exfoliate, earned it its name. Vermiculite means worm in Latin.

When processed vermiculite is added to potting soil, it retains and releases moisture and nutrients. It can hold as much as three to four times its weight in water.

It can also be used to break up dense clumps of soil. In doing so, it opens up potential passageways for young roots.

Horticultural-grade vermiculite comes in a variety of sizes. The granules may be fine, small, or large. The finest vermiculite granules are just a fraction of a millimeter. Whereas, the large ones are nearly a centimeter in length.

What are the benefits of using vermiculite?

Improved Aeration

The tiny air pockets in vermiculite make it a great amendment for dense or heavy soil. If you’re looking to maximize root growth, then consider using add a ratio of 1/3 or 1/2 vermiculite to your potting soil.

Vermiculite will decrease your soil’s density while increasing its drainage. It will make it easier for plant roots to expand and anchor.

Depending on the size of the particles, vermiculite retains 30% to 50% water. The remaining cavities contain air. They help decrease the density of soil while simultaneously increasing its volume.

Because of its aeration qualities, coarse vermiculite is suitable as a soil amendment in clay. Since clay is naturally dense and moist, the vermiculite helps break it up.

Better Moisture Retention

Since vermiculite can hold two to three times its weight in water, it is often used to improve naturally dry soils. Vermiculite’s ability to absorb essential nutrients makes it a fundamental media for plants.

Vermiculite’s capacity to retain water makes it an excellent option for hydroponic setups.. Since vermiculite has a high cation exchange capacity (CEC), you can decrease your feed times when it is your sole foundation.

Faster Germination

Seeds tend to germinate faster and more efficiently when planted in vermiculite. That’s because vermiculite offers them a consistently moist environment. When germinating seeds, most growers use vermiculite on its own. However, you can also mix the material with organic potting soil.

Keep in mind that vermiculite does not contain any essential nutrients. With that said, seedlings are more likely to develop stronger, more resilient roots when they are started in vermiculite.

Slowly Releases Nutrients

Vermiculite is responsible for adding magnesium and potassium to the soil. Its high cation exchange capacity enables it to hold on to positively charged nutrients. In doing so, it prevents valuable nutrients from leaving the soil.

Improved Growth

Vermiculite’s ability to aerate and irrigate plants make it an ideal planting medium. With better soil conditions, roots can grow more vigorously. It can even be added to the surface of a lawn to improve the vitality of newly planted or struggling patches of grass.

It’s important to remember that vermiculite is not a reliable growing medium for all plants. Specimens that require ample airflow or temporarily arid conditions would do better with an airy amendment, such as perlite.

A Permanent Solution

Unlike most organic soil amendments, vermiculite does not break down. If you want to improve your soil’s density, vermiculite is an excellent option.

Since vermiculite slowly releases minerals and moisture, it is also an incredibly reliable source of sustenance for plants. If you’re the type of grower who frequently forgets to mist your plants, then vermiculite may be right up your alley.

Fends off Fungus and Disease

Horticultural-grade vermiculite resists the buildup of fungus and other moisture-born plant diseases. It also improves soil aeration. In doing so, it automatically corrects the very conditions that cause these issues.

One of the most common issues with seedlings is a white fungus. This white fungus typically grows on the top layer of soil. While consistent moisture is essential for germination, it is also a breeding ground for harmful fungi.

If white mold is left to grow, it will eventually choke out young seedlings. As such, it often leaves growers with a total loss.

Vermiculite is a reliable remedy. Just sprinkle a small amount on the surface of your plant cells. This will help the soil retain moisture while simultaneously fending off the white mold. With vermiculite on your side, you can run a fan without drying out your plants.

What is Perlite?

Perlite is another horticultural material is often compared to vermiculite. Perlite is a product made from amorphous volcanic glass.

When perlite is heated, its density decreases. Perlite slowly releases water and nutrients to plants. Perlite slowly releases water and nutrients to plants. Its main role is to loosen and reduce the density of the soil.

What are the Differences Between Perlite and Vermiculite?

While perlite and vermiculite are often used interchangeably, there are some key differences between the two soil amendments.

Both of these amendments help to aerate the soil. Both substances have incredibly low densities. As such, they also help to reduce the weight of dense soil.

Both substances also retain ample amounts of moisture. As such, they are used to hydrate soil and perk up nutrient levels in plants.

Perlite and vermiculite also have incredibly low densities. They both can be used to lighten and aerate dense dirt and clay.


Vermiculite is a brown, flaky substance that crumbles under pressure. It darkens when it’s wet and sometimes appears shiny. Perlite has a dramatically different look.

Harvest and Processing

You already know that vermiculite is mined from raw earth. However, it undergoes an intense heating process before it is ready for agricultural applications. First, it is chopped into small flakes.

Then, it is heated to over 2,700 degrees. At which time, the water inside the vermiculite particles begins to evaporate. This expansion is referred to as a phenomenon called exfoliation.

On the other hand, perlite is harvested from accumulations of volcanic glass. After it is gathered, it is heated to temperatures as high as 1,650 degrees.

The heat causes the trapped water to expand. With nowhere to go, the evaporation causes the perlite to pop and expand. This phenomenon causes small air pockets to form.


Both perlite and vermiculite have airy, light compositions. Their ample air pockets help to reduce the density of soil. With that said, vermiculite is a far more absorbent substance.

With so many of its air pockets susceptible to water, vermiculite is the perfect product for thirsty plants. On the other hand, perlite is the preferred amendment for plants that demands more arid conditions.

Another key difference between perlite and vermiculite is their nutrient makeup. While perlite has a neutral pH and virtually no nutrients, vermiculite harbors trace amounts of potassium, magnesium, calcium, and ammonia.

Vermiculite enables plants to access essential nutrients. Plants with a vermiculite base tend to grow more vigorously.

Is Vermiculite Safe to Use in the Garden?

Years ago, the EPA found trace amounts of asbestos in horticultural vermiculite. Pure vermiculite does not contain asbestos. However, it is often mined from areas that contain asbestos.

The discovery of asbestos in vermiculite sparked consumer concerns. Airborne asbestos can cause people to develop a rare and troublesome disease called mesothelioma.

It takes many years for mesothelioma to develop. As such, many people do not realize the adverse effects of asbestos until long after their exposure.

You may have seen television commercials for lawyers promising compensation for people with asbestos-related mesothelioma. Don’t let the claims trouble you. Almost all of the vermiculite containing asbestos was retrieved from the now-defunct Libby Mine in Montana.

After the EPA’s findings, Libby Mine was closed. Since then, the EPA has ruled that the remaining horticultural vermiculite products contain little to no asbestos.

Safety Precautions

Naturally, the EPA findings have led consumers to take extra precautions. If you’re concerned that you may inhale asbestos, wear a face mask when pouring or mixing vermiculite.

Keep your vermiculite out of reach. Ensure that it is not accessible to pets and children.

How to Plant Seeds in Vermiculite?

Vermiculite is an excellent planting media. It comes in handy during every stage of the growing process. It’s the perfect foundation for young seedlings.

It doesn’t matter if you’re preparing an outdoor garden, container plants, or hydroponic setup. Vermiculite will help you grow healthy seedlings.

Getting Things Started

Many people prefer to grow seedlings in vermiculite. To do this, you will need a shallow, waterproof container, such as a plastic tray, plastic cup, or Tupperware container.

Fill the container with vermiculite. Then, sprinkle it with water. The vermiculite granules will absorb a generous amount of liquid.

When the vermiculite is wet, place well-spaced seeds on the surface. Then cover them in a thin layer of even more moistened vermiculite. After that, place a plastic cover or piece of plastic wrap over the top of the plant.

This ensures that heat and moisture can circulate throughout the soil. In doing this, you create a perfect environment for germination.

When adding water to vermiculite, you need to ensure the container and seeds do not become oversaturated.

All of the moisture should be locked into the planting medium. While moisture is essential to the growing process, a pool of water can inhibit growth.

Keep in mind that vermiculite does not contain any essential plant nutrients. You will need to mix it with soil or fertilizer when using it as a permanent growing media.

Fostering Growth

While vermiculite makes the planting process simpler, you cannot just set it and forget it. Whenever seasonally necessary, place your vermiculite-based seedlings near an indirect source of heat. After that, watch and wait.

Check the details on the back of your seed package to see how long it will take for your seeds to germinate. While you’re waiting for your plants to sprout, prepare your garden beds or containers for your new baby plants.

Transferring to a Permanent Home

When your seeds finally sprout, it’s time to make a few changes. Remove the cover from your plants. Then, transfer them to a warm, sunlit area.

You want your seedlings to develop a healthy stem and a pair of leaves before you transfer them to a permanent location. It’s a wise idea to let them ride out their earliest days in sweet vermiculite-derived homeostasis.

Creating the Perfect Potting Soil Mixture

Vermiculite can be mixed with soil or other amendments to create a rich growing medium. We recommend combining vermiculite, soil, and peat to create an inexpensive yet high-quality potting soil.

Keep in mind that your ideal soil is going to vary depending on what you’re attempting to grow.

Use the Right Grade

Vermiculite is available in three different grades, including fine, medium, and coarse. The fine particles range in size from 0.5 to 4 millimeters.

Ironically, the smallest granules retain the most water. As such, the small ones are an excellent amendment for loam or sandy soil.

The medium particles range in size from 1 to 4 millimeters. Meanwhile, the large particles can be as large as 8 millimeters.

If you are concerned about excess water retention, it’s best to opt for the coarser option.

Adding Vermiculite to Soil

If you’re mixing your potting soil, aim to create a mixture of about 25% vermiculite and 75% soil. While many packaged potting soils feature vermiculite, they can be expensive.

When you make a homemade potting mix, you save money and reduce waste. Not to mention, you have complete control over your amendments.

Vermiculite’s high moisture content makes it a dependable option for plants that love water.

Cacti, squash, tomatoes, and other drought-loving plants don’t fare well with a base of vermiculite. Meanwhile, lettuce, cabbage, grass, and other water-loving plants can benefit from vermiculite.

Where Can You Buy Vermiculite?

The EPA’s findings have made it difficult for consumers to access this incredible growing medium. However, we’ve got tips and tricks on finding stockpiles of vermiculite in your neighborhood!

Big Box Stores

Many big box stores pulled vermiculite from their shelves following the EPA’s 1980 findings. Today, many of these stores have resumed the sale of vermiculite. However, some still only offer limited provisions.

Horticultural Stores

The fastest way to get your hands on a bag is to visit your nearest horticultural store. Farm stores, hydroponic shops, co-ops, and garden centers also carry garden-grade vermiculite.

Direct from the Distributor

Many vermiculite manufacturers will ship orders directly to your door. Dicalite, Whittemore Company, and Pleasant Hearth are just a few of the more popular manufacturers of horticultural-grade vermiculite.


Online shopping is another easy way to score some garden-grade vermiculite. Just be sure to order from a trustworthy distributor.

Final Thoughts

While this growing medium sometimes gets a bad rap, it can be the saving grace of your indoor plants.

Vermiculite’s ability to slowly release moisture puts it in a plant media class of its own.

Its ability to break up and loosen soil deserves a standing ovation.

This so-called wormy horticultural product is an excellent soil amendment as well as a reliable seed starter.

Pick up a bag today! You won’t regret it!

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