Categoriesbasics perlite soil-less media

Today we will discuss what is perlite, and what are some of the main perlite uses. Sometimes vermiculites are also used in place of perlite. The purpose of these additions is more or less the same.

Ever bought a bag of a good quality potting mixture? Then you must have found some small white balls just like styrofoam, in that mixture.

Those small things are there not by any coincidence, rather it has been added to the mixture to make it more conducive to aeration. These small styrofoam-like balls are nothing but perlite.

Though it has many uses, we will focus only on the uses of perlite in gardening and horticulture.

What is Perlite?

Perlite is naturally occurring siliceous amorphic volcanic rock. But unlike other volcanic glasses, if heated them above a point (8000-9000 C), they expand up to 20 times of its original volume.

How it is made?

The perlite is made when the volcanic lava emitted from the volcanos, cools down rapidly, in a cooler atmosphere. Due to this rapid cooling, the water vapor got trapped inside the rock and the whole molten rock transforms into a glass-like structure.

What is Perlite Made of?

As an amorphic volcanic glass, perlite is mostly made of silica or SiO2 (about 70-75%). Other than you will also find a mixture of Aluminum Oxide or Al2O3, and Oxides of Sodium, Potassium, Iron, Magnesium, and Calcium, and moisture.

The perlite we use in gardening is not the same as it is found in nature. Perlite is a natural volcanic glass. These tend to have more water in them than other types. In nature, they are grey or black in color and is very dense and heavy.

How to Make Perlite Suitable for Horticulture?

You can not use nature’s perlite to grow plants. What we use in growing plants is called expanded perlite. Once the dark grey perlite is heated at a temperature above 850 deg C it becomes soft.

The water that was trapped inside the rock vaporizes and tries to escape. As a result, the rock expands more than 10 times their initial size. This expansion of the rock also creates its most distinguishing feature; its unique white color.

Expanded Perlite has many tiny air chambers. These tiny cells that absorb moisture on the exterior of the particle, and prevent it from entering inside. That is why it is particularly useful in providing moisture to plant roots.

This expanded perlite is much lighter in weight and becomes porous. You can crush these with normal pressure. The best part is it is clean, sterile, lightweight material and doesn’t decay or shrink.

Is perlite toxic?

Perlite is not toxic. However, protect your eyes and mouth while using it. Perlite can create eye irritation and respiratory problems if you ingest.

Where Can I Buy Perlite?

Finding perlite for plants should not be a problem for any gardener. They are mined throughout the world. Countries like Greece, the USA, China, and Turkey are the forerunners in this.

You can buy perlite at your garden store nearby or you can buy it online. Don’t forget to read the product details thoroughly while buying.

Various Perlite Uses:

Because of its low density and low price, it is used for many commercial applications. Some of the main perlite uses are in building and constructions, horticulture, filters, and filter aids. In gardening and horticulture, perlite is used for many reasons.

How does perlite work?

Perlite works by filtering the excess water out of the soil and holding some water and nutrients in its cavities for plants to absorb. These nutrients are essential for plants, especially when they are grown in pots or on raised beds.

Advantages of Perlite Soil in Gardening and Horticulture:

Adding perlite to your garden has some undeniable benefits. Here are some reasons why you should use it in your garden

Perlite encourages quicker germination than any other growing media. You can experience quick seedling growth. It can be used by mixing with peat moss, or coconut coir, or use as potting soil. You can also use it solely to germinate seeds.

Perlite soil is inorganic, inert, and sterile. It naturally contains the different minerals which are essential for the growth of the plant. Being inorganic it is free from weeds, diseases, and pests.

It is non-toxic and there are very few fire hazards.

Unlike peat moss, perlite soil does not decompose very easily (if at all) so you can store and use it for many years.

Perlite soil mixtures have very good aeration and drainage facility. Adding perlite is probably the quickest way to increase the drainage of your garden soil. This is particularly helpful in raised beds or container planting.

It is almost pH neutral. So you can use it to reduce the soil-acidity.

Disadvantages of Perlite Soil:

There are some of the disadvantages also of using perlite as growth media.

Perlite holds water by having a large surface area and within the nooks and crevices of vast pores. But being porous and made of volcanic glass it allows the excess water to drain away much quicker than any other media. So if you have really thirsty plants, investing in perlite might not be a good choice.

It is a non-renewable resource. So you can not increase its availability as per your likings like that of coconut coir.

While using perlite, eye and mouth protection are recommended, if you don’t want to ingest any of the dust. The dust can create respiratory problems and eye irritation. Use respirators like this to protect yourself while working with it.

Types of Perlite: Coarse Vs Fine:

The coarser the perlite better the air porosity. It will be beneficial for your plants in terms of drainage and root growth.

This is a very good choice if you are planning to grow orchids or succulents. The main downfall of using coarse perlite is it doesn’t blend well with the soil.

The finer perlite has its own benefits. Its mainly used in creating potting mixes and seed starters. You can mix both garden soil or potting soil with perlite to improve their drainage capacity.

How Much Perlite to Add to The soil?

For growing plants you can add from 10%- 50% depending on your need. The more the percentage of perlite, the more will be airflow for the roots but on the flip side, you have to add more nutrients because most of the nutrients will be drained out with the excess water.

Add 10-20% if you want to add fewer nutrients and water to your mix. Whereas if you go for a 30-50% mix, your soil will get lots of airflows (excellent for the roots) but you have to add nutrients and water more frequently.

Perlite Vs Vermiculite:

One alternative to perlite is vermiculite. Some gardeners prefer to use vermiculite over perlite because of their water retention capacity. Vermiculite generally retains more water so it makes them a perfect choice for seed starters. They can also absorb nutrients along with water.

Vermiculite is a very good option if your plants need lots of water. Mixing perlite with vermiculite makes it a more balanced media. Vermiculite absorbs water and nutrients whereas perlite makes sure that the excess water drains away. They are more of a complementary to each other than an alternative.

How long does it last? / Does perlite decompose?

Perlite is inorganic and does not decompose with time, so it is a good choice for growing plants.

Use of Perlite in Hydroponics:

Perlite uses in hydroponics is very popular nowadays. In case you have never heard about hydroponics, this is a method of growing plants in an enclosed growing space, a controlled environment, and with very little water.

Because of its moisture-holding capacity, it is an excellent growing medium under these conditions.

Perlite is used in hydroponics mainly to propagate plants. As roots start to grow in search of a water source, a well-draining media like coarse perlite forces them to grow rapidly. It prevents plant roots against rot.

Other Perlite Uses:

It is an excellent filtering agent. Perlite loose-fill insulation is used in the hollow cores of concrete block or cavity type masonry walls.

Besides as a seed starting material in horticulture, Perlite filters are used in many places to filter beer before getting bottled.

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