Perlite is one element you don’t want to overlook when planning your spring garden. Growing flowers, fruit, or vegetables will be so much easier when you add this key component to your soil mix.
Dive into this post for a breakdown of everything you need to know about this mighty mineral and why your garden shouldn’t be without it.
What is Perlite?
Open a bag of potting mix from the store and you’ll likely see a bunch of little, white balls mixed in the soil resembling bits of Styrofoam. Your eyeballs are beholding perlite, a lightweight, inorganic, soil amendment that improves your soil’s structure by providing aeration and drainage.
Helping stuff grow is high on perlite’s list of things to do. However, this does not make it a fertilizer because it does not add microbial or nutritional value to soil or plants.
Keeping your soil’s structure light and loose is this beauty’s wheelhouse. Think of it as a cousin to compost. They both circulate air between a plant’s roots to promote healthy growth.
Safe for organic gardening, perlite’s low density traps air in soil mixes. In addition to keeping your soil light, it promotes drainage.
How does it pull off such an amazing and essential task? Take a trip back to Biology 101 and find out for yourself.
Pop a piece of perlite under a microscope and prepare to rest your peepers on a vast network of tiny cavities. These holes help it retain up to four times its weight in water.
As a result, it transfers moisture to plant roots very well. Also, it captures and stores nutrients that would have been washed away.
Porous by nature, perlite gets rid of excess water faster than potting media such as vermiculite thereby preventing waterlogging. Say goodbye to fungal diseases and root rot.
Depending on the grade of perlite you buy your soil will experience a different level of drainage. You can find perlite in four grades. Also referred to as granule sizes, these grades have a corresponding level of coarseness.
Fine perlite: This delicate perlite with its smaller particles works well for rooting cuttings or starting seeds. Size #1 perlite is a 1 inch to 1/8 inch particle.
Prepare to go on a bit of a treasure hunt to find it as a standalone product. A similar item that you will find much easier to locate is fine pumice. Look for a label indicating that it is used for succulent or bonsai planting.
Medium perlite: Peer into a bag of commercial potting soil and you will typically spot medium-grade perlite. It is grade #2 and comes in the size of a 1/4 inch to 3/8 inch particle.
Gardeners find that this works well as a great all-around size for window boxes, potted plants, and general garden use.
Coarse and super coarse and perlite: Amend dense soils and garden or raised beds using this high water-retaining perlite. You will find that the coarse perlite is a grade #3 and is a 1/2 inch particle.
Super coarse perlite is a grade #4 and is a chunky one-inch particle. Reserve this type of perlite for use in extremely heavy soil.
Bear in mind that smaller and lower quality grades of perlite can kick up a bit of dust. Wear a pair of protective glasses, gloves, and a dust mask if you are sensitive to fine particles floating around in the air.
Don your gloves and dust mask when working with perlite to prevent being irritated by the dust it can kick up as you’re handling it.
Perlite can be dusty, so be sure to wear gloves and a dust mask when working with it. Keep the dust down by misting it with some water before you mix it.
How is Perlite Made?
This naturally occurring mineral is a popular non-renewable resource and can be found being produced all over the world. You will find the highest concentrations of perlite production in Greece, Japan, Turkey, and the United States.
Inexpensive and multi-functional, it serves the needs of gardeners and builders alike. A lot of companies add it when manufacturing ceiling tiles, plaster, and masonry to improve stability or act as an insulator.
Its filtering capabilities make it a great media for swimming pool and beverage filters. Before it can be used in these different ways, it has to be processed first.
In its natural state, perlite is an amorphous, dense volcanic glass. It’s a byproduct of lava. When lava cools, it forms obsidian and when obsidian comes in contact with water, it forms perlite.
This volcanic glass is black or brown, has a very high water content, and is heavy. Through an intense manufacturing process, perlite transitions from a very heavy, dark substance to a very light, white element.
How does this happen?
Manufacturers crush perlite first. Next, they bake it in big ovens. Heating the mineral very rapidly to a range of 1,560-1,650° Fahrenheit makes it soften.
It also makes the water inside it evaporate into steam and escape which causes the material to expand up to 16 times its original size.
The air that is trapped inside changes the color of perlite from dark to a brilliant white. This interesting transition happens because of the reflectivity of the water that’s still stuck inside the glass.
As a result of this heating process you get the tiny, white balls you see in potting mixes. These foamy, lightweight balls are sterile and do not shrink or decay.
Perlite may start out dark and dense, but when the manufacturing process is over, it looks light and fluffy as you see pictured above. Creative Commons Perlite für Zimmerpflanzen by Maja Dumat / CC by 2.0
Although you can crush them by applying moderate pressure, you can expect them to hold their own when placed under the light strain of being mixed in with other soils.
What are the Benefits of Using Perlite?
One of the main benefits of using perlite is that it offers excellent drainage for plants. A natural filtration system, perlite allows excess water to easily drain away from the soil while holding onto a smattering of moisture as it grabs nutrients the plant relies on to grow.
Container plants particularly benefit from perlite. They thrive in a well-draining, light, and nutritious soil mix. Perlite gives the soil the drainage it needs while helping make the soil lighter and fluffier.
Lacking additives or toxic chemicals, it is a good all-natural product that helps support your plants on their path to health and maturity. Growing flowers, herbs, and vegetables in container pots will be much easier when you add this precious mineral.
A neutral pH makes it agreeable for use in any container or garden. Perlite improves the soil’s airflow which helps the roots of your plant breathe better.
Healthy root development depends on excellent aeration, which perlite supplies. Oxygen gives life to root systems as much as water does.
Cells in the roots depend on the soil to give it life-sustaining oxygen that releases much needed energy to promote growth and healthy nutrient uptake. Cells can’t get too much oxygen but they can get too much water which could oversaturate the roots.
This can lead to root rot which can kill your plants.
Adding perlite to your potting mix will lock oxygen into the soil and give water the outlet it needs to drain out. Doing so will also benefit microorganisms that live in the soil and depend on oxygen to thrive.
Providing oxygen to plant roots and awesome drainage to the soil sounds great, but perlite does more than that. Add it to your oversize plant containers for some lightweight volume to fill it out a bit without breaking the bank.
Using high-quality potting soil to fill up a large container can get costly, making perlite a rather good looking option. Put perlite at the bottom of your container instead of cobbles or pebbles which can easily make a container very heavy.
Doing so works wonders for adding extra volume without packing on the weight. Adding a bit of potting soil to the perlite will help tall containers not become top-heavy.
Your houseplants that are not re-potted frequently will appreciate that it does not decompose. Saturated or heavy soil won’t make it become unstable or lose its shape.
Plus, the material looks just as nice as decorative pebbles or sand without costing as much money. Place it on top of a lovely ornamental container housing one of your favorite plants. You will create a modern, fresh vibe worthy of any garden.
How Do You Use Perlite in the Garden?
Combine vermiculite, perlite, and peat moss in equal parts to fortify your soil mix. You will create a good foundation to grow your seedlings so they can receive the support needed to develop into healthy plants.
This mixture will help your plant absorb nutrients and ward off disease. Feel free to also add it to the top layer of your soil. Eventually, it will delve into the potting soil where it will support drainage and water retention.
Moreover, perlite can be used to propagate your plant cuttings by supporting root growth. Root your cuttings in a small jar after filling it with dampened perlite.
What Type of Perlite Do You Use?
Plants such as succulents do well with coarse perlite added to the potting mix. They benefit from the drainage and high porosity this incredible mineral offers the soil.
Excellent drainage and high porosity make this type of perlite a no-brainer. The bigger size makes it less likely to get caught up in the wind and blow away.
However, fine perlite has its perks as well. You will find that is well suited for rooting cuttings and quality seed-starting mixes.
The drainage it encourages prompts fast root production. Scatter this type of perlite across your lawn and in time it will dive into your soil and improve its drainage.
Where Do You Buy Perlite?
Get your perlite from a plant nursery or local garden center. Avoid the soil or soilless blend and opt for 100% perlite.
Finding perlite locally may not always work out well. Shop online for it if you find that to be the case. Here are some good options to try.
xGarden Horticultural Grade Premium Perlite 8 Quarts
This coarse and chunky perlite comes pre-washed so it’s free of excess dust. Sterile and non-toxic, it lightens soil while improving plant and root health.
Expect your soil to experience better drainage and aeration after using this premium perlite soil additive. Your plants will appreciate how well it helps the soil hold onto moisture and nutrients for later use.
Just remember before buying it that coarse perlite is a much bigger size than fine perlite. Of course, if the particles end up being bigger than you’d like you could always crush them—but who wants the extra work?
Espoma PR8 Organic Perlite 8 Quarts
Espoma’s perlite works well for those who want to only use organic material in their gardens. This 100% all-natural beauty aerates the soil quite well and promotes strong root growth.
Add it to your potting mix to help loosen heavy soil and prevent compaction. This perlite is not as big as the coarse type so it can work well lightening up the soil for easy rooting.
Mother Earth Coco Plus Perlite Mix
This compaction-resistant mix is great for both indoor and outdoor container gardens. You will like how it provides strong aeration and good drainage.
Overwatering is hard to do with a high-quality perlite mix such as this one. Prepare to amp up your growing game because this light and fluffy mixture helps plants grow stronger and faster.
Buy your perlite in bulk. Save the rest. As the seasons change, you will discover a lot of different uses for it in your garden.
Adding this amazing soil amendment to your yard will make a big difference in the health of your garden. The improvement in drainage and aeration may have you singing its praises nonstop.
Your seedlings and plants will appreciate the extra tender loving care too. Remember that you can easily use it in your potting mix or use it by itself to promote the healthy growth of cuttings. Add this secret weapon to your gardening toolkit and prepare to be impressed.