Categoriessoil-less soil-less media vermiculite

Today we will talk about Vermiculite, one of the growing mediums that is not talked much about. If you are not aware of what is vermiculite and what is the use of vermiculite in gardening please read on.

This is a part of our Soil-less growth mediums series.

Though sometimes perlite and vermiculite are used as synonyms, they are very different in many aspects. Through this article, I wanted to put some light on these.

What is Vermiculite?

Vermiculite is silicate material which is used in horticulture as growing media. The name originates from the word vermiculture which means to breed worms.

Vermiculite can hold potassium, Calcium, Magnesium, Ammonium which are needed for plant growth. The color, composition, and pH of vermiculite vary from mine to mine.

Is Vermiculite Toxic or Is It Safe To Use?

Vermiculite itself is not dangerous and is safe to use. Earlier when vermiculite was mined, the ore often contained asbestos. Asbestos is harmful and can cause lung cancer and other diseases if inhaled. And so vermiculite was said to be dangerous.

Nowadays vermiculite is mined under strict industry protocols and is very safe to use.

Is Vermiculite Organic?

Vermiculite by nature is inorganic. It is sterile and inert.

How Vermiculite is Made?

Technically, vermiculite refers to a large group of hydrated laminar magnesium-aluminum-iron silicates, that somewhat looks like mica. You cannot use this vermiculite for growing plants.

Horticultural vermiculite is made by exfoliating the vermiculite rocks. After mining, vermiculite rocks are heated at a temperature above 1100 deg F. At this temperature the water inside the vermiculite rocks becomes steam and expands the rock into worm-like particles.

Types of Vermiculite:

Vermiculite can be of two basic types:

Crude vermiculite Exfoliated Vermiculite

1. Crude Vermiculite:

Crude vermiculite is vermiculite that has not been heated or expanded. This type you cannot use as growing mediums.

Crude vermiculite can be of five primary grades viz. large, medium, fine, superfine and micron based upon particle size.

2. Exfoliated Vermiculite:

Exfoliated vermiculite is the variety of vermiculite that has been treated with heat. This variety is widely popular among gardeners.

Exfoliated vermiculite can be of different grades. Like crude vermiculite, exfoliated vermiculite comes in micron, superfine, fine, medium and large grades. Just remember, finer grades will be more compact than the larger grades, which help reduce soil compaction. What grade is best for you depends on your soil conditions.

Vermiculite grade Particle size (in diameter) Large Grade ½ inch Medium Grade 3/10 inch Fine grade 1/10 inch or less

How To Sterilize Vermiculite:

If you want to sterilize vermiculite you can do it in two ways.

Sterilize Vermiculite Using A Gas Oven:

Heat up the vermiculite to reach a temperature above 180°F and sustain that for 30 minutes. It will also kill seeds, insect eggs, and larvae.

It is a popular method for sterilizing vermiculite. A word of caution, sterilizing vermiculite can create a lot of odor. So make sure you are doing it outdoors and not in your kitchen.

Sterilize Vermiculite by Using A Microwave Oven:

You can also sterilize by microwaving moistened vermiculite for three to five minutes, depending on your microwave’s power rating.

The advantages of microwaving the vermiculite are that it is faster than oven treatment, and as it is portable you can reduce the odor.

Just remember, while sterilizing, microwave ovens can heat up quickly, but they also leave cooler spots that can be very hard to find. And also this process only works with a very small amount of vermiculite. If you have a very large amount of vermiculite you can try solarization method for sterilization.

Use of Vermiculite in Gardening:

Vermiculite can retain more water than perlite. Its retention of water makes it good for sustaining the growth of seeds. It contains useful trace minerals. Its color is not as obvious as perlite. It is generally cheaper than perlite.

You can combine exfoliated vermiculite with peat moss or coconut coir and make a good soil-less growth media. This can be used in the home as well as professional gardening uses.

Vermiculite can be a good media for seed germination either used solely or with combination with other media. You need very little watering for growing in vermiculite. Vermiculite does not rot or turn moldy and it helps the roots of the young plants to anchor and grow.

They can be used as a soil conditioner. A little mixing of vermiculite can make your heavy, sticky soil breath-ably light. It creates air channels and thus improves aeration.

Although not every time, in many cases vermiculite is found to be infested with asbestos which sometimes related to asbestos-related diseases, like mesothelioma. It is also far heavier when compared with perlite so durability problem is always associated with it. At times it can trap too much water leaving the media as soupy soil.

How Does Vermiculite Works?

Vermiculite works with both dense and loose soils but in different ways. The surface of the exfoliated vermiculite allows it to hold a large amount of water. It then slowly release it back into the soil to your plant’s roots. This feature of vermiculite makes it ideal for loose soil like sandy and loamy soils.

On the other hand, It also helps aerate the soil and loosen up the dense soils such as clay. This added aeration can give roots better access to nutrients and prevent waterlogged soil, helping plants thrive.

How much vermiculite to add to soil:

Use 1/3 to 1/2 vermiculite in your potting soil for containers or when building your raised beds, or improve your garden soil by adding it in the spring with your other soil amendments and compost.



How to Use Vermiculite

Vermiculite along with perlite is very good for soil amendment. They can be used in several ways throughout the garden — indoors and out — depending on your needs.

In a container put some of the vermiculite and add some water. It’s best to dampen the vermiculite before using it.

Mix Vermiculite, coarse sand and coco coir in 1:1:1 ratio in a container (a wheelbarrow is a good choice for this type of work). Now fill seed-starting trays or small pots with this mixture. This will be used for germinating seeds indoors.

If you are planning to plant seeds directly in the garden, add a little layer of vermiculite when starting seeds outdoors. This will prevent your garden soil from forming a crust.

You can create a good quality potting mix by mixing equal parts of vermiculite and peat moss and a handful of slow-release fertilizer granules.

Vermiculite can also be helpful in amending the container soil. Add 50 per cent vermiculite to your container soil. If you have sandy soil it will improve its water and nutrient-holding capacity. Whereas if you have clay soil, this will increase the drainage of the soil. If you want to amend garden soil outdoors, you can put a 3-inch deep layer of vermiculite for 6- inch deep topsoil.

Things You Will Need for Applying Those Ideas:

Wheelbarrow or container

Shovel

Seed-starting trays or pots

Remember:

Always use horticultural vermiculite. Vermiculites that are meant for construction do not perform very well in the garden.

Why Add Vermiculite To The Soil:

The primary reason we add vermiculite to the soil is that it improves the water holding capacity as well as the aeration of the soil. So it basically improves your soil quality. Vermiculite also helps in faster seed germination.

Vermiculite Uses For Plants: How Does Vermiculite Help Your Plants?

Apart from holding water, vermiculite can also hold calcium, Magnesium, Ammonium etc that are crucial to the plant’s nutrition. So vermiculite helps the plant in quite a few ways:

It increases the rate at which the seeds germinate. It helps the roots by providing good aeration to the soil. Holds up essential minerals for the plants.

Where to buy vermiculite:

Vermiculite is mined in the United State, Brazil, Zimbabwe, China, and South Africa. They are generally clean, odorless and non-toxic by nature and are marketed in the form of brown cubes.

The best place to buy vermiculite is at your nearby garden store or nursery. Talk to your nurseryman about the type of vermiculite and what suits your needs. Alternatively, you can buy it from amazon.

Other Uses of Vermiculite:

Apart from Gardening, vermiculite is used as insulator worldwide. Other usages include uses as packaging material, a substrate for incubation of eggs, waste treatments etc.

Thanks for reading. Hope you enjoyed the article.