Perlite and Vermiculite, both are well-known to seasoned gardeners. These two materials are harvested naturally from rocks.
People write to me always to know what differentiates the two and what their usage cases are. Let’s see how they are different from one another and how you can use them to your benefit.
Perlite vs Vermiculite
Listed below are the key differences between Perlite and Vermiculite.
| Perlite | Vermiculite |
|---|---|
| Perlite is white in color and made out of mined volcanic rocks. | Vermiculite is brown/beige in color. It is made by super-heating Biotite or Phlogopite. It expands and turns into dry flakes. |
| Perlite is harder relatively. | Vermiculite has soft, sponge like texture. |
| Perlite is slightly alkaline in nature(7-7.5). | Vermiculite is almost neutral in nature. |
| Perlite doesn't hold moisture well for longer periods. | Vermiculite is good at holding a lot of moisture(3-4 times its volume!) for longer periods of time. |
| Perlite releases water gradually and raises the humidity. So it's good for plants that need humid conditions. | Vermiculite holds water for longer hours, thus it's ideal for plants that need moist soil. |
| Perlite aerates the soil well. | Vermiculite holds moisture but doesn't aerate as well. |
| Perlite works well for rooting cuttings. | Vermiculite works well to start the seeds as it keeps seeds from drying out during germination. |
| Perlite is suitable for shade-loving houseplants, succulents and cacti to prevent root rot and fungal diseases. | Vermiculite is suitable for plants that are sensitive to alkalinity in the soil. |
| Use Perlite if your garden is in wet climate. | Use Vermiculite if your garden is in dry climate. |
| Perlite adds drainage to the soil that it has been added to. | Vermiculite mixes with the soil and helps retain moisture. |
Perlite or Vermiculite for Vegetables
Observe which works for you better as per your weather conditions and soil condition. They both may seem similar but have distinct properties.
Perlite works well for rooting cuttings. This is because it adds drainage to the soil it has been added to. Thus the plant stays safe from root rot.
Vegetables like Lettuce, Celery, Ginger, Garlic, Avocado, etc. grow wonderfully in soil medium that contains Perlite. These vegetables can be grown from cuttings.
Vermiculite can be used separately or can be mixed with soil/peat to enhance moisture and nutrient retention of the soil.
Vermiculite is an ideal soil amendment for seed germination. Use Vermiculite in the soil if you are growing vegetables from seed.
Is Perlite safe for growing vegetables?
Perlite is safe for growing vegetables as it’s mined from rocks and doesn’t have any chemicals in it. Use Perlite according to the instructions and your vegetable plants should be fine.
Perlite or Vermiculite for tomatoes
I’ve tried both on my tomato plants. I can say Vermiculite works best for tomatoes. A mixture of Perlite and Vermiculite works too.
Vermiculite enhances the environment for seed germination. But keep in mind the weather and soil conditions before making a choice.
Also, if you want to germinate tomato seeds, add Vermiculite to the soil. If you grow them in pots by taking cuttings from existing plants, Perlite works wonders.
Perlite vs Vermiculite for rooting cuttings
Perlite works best for rooting cuttings of plants. Perlite doesn’t hold moisture for longer periods, making it ideal for rooting cuttings.
Too much moisture/overwatering rots the roots of the tender plants. Perlite aerates the soil well and it’s an ideal choice for rooting cuttings.
Vermiculite is more suited to grow plants from seeds. To conclude, if you want to root your cuttings, use Perlite.
Perlite or Vermiculite for Houseplants
Vermiculite mixes well with the soil and helps retain moisture. Perlite enhances the draining ability of the potting mix.
So, both have different use cases. You need to use them based on the plants you have as they have distinct properties.
Is Vermiculite good for indoor plants?
Vermiculite is for houseplants that enjoy a lot of soil moisture like the Irises and Forget-me-nots.
Add Vermiculite to the potting mix if the plant is suffering/likely to suffer from underwatering. Vermiculite helps to lock the moisture in the soil.
Is Perlite good for indoor plants?
Perlite is suitable for shade-loving houseplants, succulents, and cacti. Perlite doesn’t retain moisture like Vermiculite but enhances the draining ability of the potting mix.
Perlite is also added to pots to prevent them from becoming top-heavy as it is a lightweight material. One can also add Perlite to the bottom of pots.
Perlite or Vermiculite for hanging baskets
Vermiculite holds water up to 5 times its volume. Vermiculite is lightweight so it’s ideal for use in hanging baskets.
I use Perlite and Vermiculite together. Mix equal parts of Perlite and Vermiculite. Add 1 part of this mixture to 3 parts of the soil mix.
My plants grow fine in such a mixture. Adjust the quantities or use only one of the additives if your plant requires special conditions.
Perlite or Vermiculite for Raised Beds
If you want moist soil for your plants, use Vermiculite. If you want to aerate the soil while still draining it well, use Perlite.
Should I add Perlite to raised bed?
Add Perlite to the raised bed if you want to aerate the soil. Perlite works wonders for rooting the cuttings. You need to add Perlite based on the plants you have in the raised bed.
If you want to grow houseplants in the raised beds(balcony), you can add Perlite to the soil. Succulents and Cacti grow well in Perlite soil mixture too.
Add 4-8 quarts of Perlite per cubic yard of soil. This way you can make sure the soil drains the excess water.
Should you add Vermiculite to raised beds?
Adding Vermiculite is a good idea to amend the soil without disturbing the soil pH. Vermiculite works best for plants that need moist soil.
If you want to grow the plants from seed it’s a good idea to amend the soil with Vermiculite. It also works best when repotting outdoor container plants.
Vermiculite works best for plants that are sensitive to soil alkalinity. Vermiculite mixes well with the soil and helps with moisture/nutrient retention.
Perlite or Vermiculite for drainage
If you want to add drainage to the soil, add Perlite to it. You can mix perlite in a ratio of 1:5 to equal proportions based on your requirement.
Perlite also aerates the soil well because of its texture. Adding Perlite to the soil saves the susceptible plants from root rot.
So, adding Perlite helps those plants that are more susceptible to root rot. Vermiculite is not that ideal if you want to improve soil drainage.
Vermiculite is for those plants that need moist soil. It’s not good if all you need is a well-draining soil.
Perlite vs Vermiculite for Mushrooms
If you want to do cakes in a shotgun fruiting chamber then plant your mushrooms on top of Perlite. Perlite assists the micro-climate.
Perlite enhances the draining ability of the medium. Vermiculite has different properties and in the case of mushrooms, Perlite and Vermiculite aren’t interchangeable.
Vermiculite helps retain moisture. If you are growing your mushrooms in coir(bulk), Vermiculite helps retain the moisture and keeps the coir from over-compacting.
People often ask me if they can use one for another. I understand that some people might not find Vermiculite/Perlite near them. But they are not interchangeable, especially for mushrooms.
Perlite vs Vermiculite for Blueberries
Perlite isn’t suitable for blueberries that grow in containers. Blueberry bush doesn’t like soil that drains excessively.
For blueberry bushes that grow in the ground, Perlite and Vermiculite both work wonders. Mix Perlite/Vermiculite in peat moss and you’re good to go.
Check the soil pH and then decide which one you should use. If the plants grow in clay soil, you may want to add Perlite to increase drainage.
Perlite or Vermiculite for Dahlias
Mixing Perlite in the soil helps prevent root rot in Dahlia plants. Dahlias do not like to be overwatered.
Root rot is a common issue for Dahlia plants. Overwatering causes waterlogged conditions, which rot the roots of Dahlia.
Root rot causes Dahlia leaves to turn yellow, which is the most common issue of Dahlias. You can amend the soil using Perlite.
Tip: Add Perlite only if Dahlias are growing in heavy(clay) soil.
I do not advise using Vermiculite to amend the soil for Dahlias. It didn’t work well for me.
Perlite vs Vermiculite for Citrus trees
Perlite and Vermiculite can be used to amend the soil for Citrus trees. Citrus plants need soil that drains well.
Soil becomes the main external factor that influences the health of Citrus trees. You can amend the soil by adding Perlite/Vermiculite to it.
You may need to adjust the amount of Perlite/Vermiculite based on the type of soil. Clay soil needs to be amended a lot to suit the needs.
Vermiculite may compact the soil over a period of time.
Perlite vs Vermiculite for clay soil
Perlite works best to amend clay soil. Perlite enhances the draining ability of Clay soil. You’ll also aerate the soil by adding Perlite to it.
Vermiculite is light in weight but also holds a lot of moisture for long hours. This is what clay soil does already.
Adding Vermiculite to clay soil doesn’t improve it in any way. Add Vermiculite to sandy soils to improve the drainage.
By adding Perlite you increase the drainage without disturbing the pH of the soil. Perlite is comprised of white flakes that increase the air circulation in the soil.
Apply Perlite to your soil once a year if you want to improve the clay soil. Applying Perlite for two/three years would suffice.
Frequently Asked Questions
People write to me many questions that relate to Perlite and Vermiculite. I thought I’d answer them all in this blog post in the hopes of helping a wider audience.
Is Vermiculite in potting soil dangerous?
Vermiculite can be dangerous if it has asbestos in it. Asbestos can be fatal to human beings, so be careful when you use Vermiculite.
Vermiculite can also be fatal to plants that hate waterlogged soils. Vermiculite holds water for too long. Plants might suffer from root rot.
Are Perlite and Vermiculite interchangeable?
No, you can’t use Perlite and Vermiculite interchangeably. Perlite and Vermiculite have distinct properties and are used to achieve different results.
Perlite increases the drainage in the soil while Vermiculite mixes with the soil and enhances water retention.
Does Vermiculite break down in soil?
No, Vermiculite doesn’t break down in the soil. It is not like compost which degrades over time. Vermiculite is extracted from rocks, so it’s pretty hard to decompose it.
Vermiculite keeps absorbing water and helps increase water retention.
Can you grow plants in just Perlite?
You can use Perlite to germinate seeds. Perlite works for this purpose because of its porous nature. Roots grow into the Perlite without hassle.
Be careful when using Perlite alone for other purposes than this. Using Perlite alone is not recommended.
What are the disadvantages of Perlite?
- It drains away a lot of water, this property may not suit all kinds of plants.
- Perlite dust can irritate the eyes and respiratory tract.
- Perlite gets washed away in excess water and windy locations.
- Perlite is a non-renewable resource.
Can I use both Vermiculite and Perlite?
I combine Vermiculite and Perlite for specific reasons. By combining them you can cater to the specific needs of certain plants.
You can adjust the water retention and drainage properties of the soil by amending with Perlite/Vermiculite.
What is better Perlite or Vermiculite?
Perlite and Vermiculite have distinct properties and different use cases. Vermiculite mixes with the soil and helps retain moisture.
Perlite helps to increase the drainage in the soil. Perlite aerates the soil because of its texture. Both are to be used for different purposes.
Choose wisely, happy growing 🙂