If you’re looking for an additive to improve the quality of your soil, or even replace it entirely, then vermiculite is an attractive option. is commonly used in soil mixes as well as by professional gardeners and nursery workers to improve seed germination success and encourage rapid root growth on cuttings.
It can also be invaluable in preventing plants from overwatering and succumbing to root rot, as it has impressive moisture retention properties that release water according to the plant’s needs. So what really is vermiculite and how can you use it to benefit your plants?
what is vermiculite?
Vermiculite is a natural mineral that takes the form of shiny flakes, the color of which varies from dark gray to sandy brown. These flakes, which are more specifically a hydrated magnesium iron aluminum silicate mineral, are heated in a specially designed commercial oven, where they then expand into an accordion shape, almost like a small accordion.
It is this version of vermiculite that is most commonly used in horticulture as a means of improving soil quality or helping seedlings take root more quickly.
how is it done?
vermiculite in its natural form closely resembles mica, with a layered rock appearance. It is mined in various regions of the world, including Russia, Australia, Brazil, Uganda, and the United States. Open pit or open pit mining is the technique used to extract vermiculite from the ground. this is because the minerals are relatively close to the earth’s surface and therefore tunnels are not required.
Open pit mines look like giant craters in the ground, where miners work to separate the ore from vermiculite and other minerals, then sort them into different categories based on size. After its extraction from the ground, the vermiculite is heated in industrial ovens, where it will change its structure. this process is called “exfoliation”. Exfoliated vermiculite transforms into tiny strands that look like worms, and that’s how vermiculite got its name, from the Latin word “vernacular,” which roughly translates to “worm-breeding.”
Once the peel is complete, the appearance of the final product will vary depending on its size. There are four sizes of vermiculite available, with the largest size having an obvious accordion shape. the smallest sizes to the human eye look like large grains of sand.
how to use vermiculite in the garden
vermiculite produced for use in the garden will always be of the exfoliated vermiculite type. it has many useful qualities that can benefit your soil and plants. it is aerator, retains moisture, retains nutrients, is light, non-toxic, sterile, does not rot or mold and has a neutral pH.
soil improvement
vermiculite can be added to poor quality soil to improve it. If you have heavy, loamy, poorly drained, or sandy soil in your garden, then most plants will have a hard time surviving, let alone thriving in this environment. You’ll often hear the phrase ‘improve your soil before you plant’, but how do you do this in practice? vermiculite is your answer. use about half the volume of the soil in vermiculite and work deep into the soil. vermiculite will dramatically improve soil aeration, allowing plants to grow much better. it will also retain moisture and nutrients needed to help feed the plant.
rooting cuttings
Vermiculite is commonly used by those in the garden trade for root cuttings. It can be used in a variety of ways, either alone, mixed with soil, or combined with bark for a soilless potting mix. Whether used alone or in a mix, propagating a cutting with vermiculite will promote anchorage for new roots and accelerate root growth. if you want to encourage faster rooting cuttings and a higher propagation success rate, vermiculite is the preferred material to use (the vermiculite association).
seed germination
Vermiculite can be used alone or in a potting mix to improve seed germination. the use of vermiculite for this purpose will make the seedlings develop more quickly. if used alone, add only a small amount of water so as not to overwhelm the seeds.
The vermiculite will release moisture to the seedlings when they need it. You should also add a few drops of weak fertilizer once leaves appear on the seedlings, to replace the nutrients that the soil would normally provide. When the seedlings are ready to be planted outside, they can be easily removed from the vermiculite without damaging the roots and planted in pots.
container gardening
Vermiculite is a great addition to potting soil, whether in outdoor containers or for indoor plants. Mixing a little vermiculite into your potting soil will improve aeration and moisture retention, resulting in a healthier root system that is better able to distribute and absorb nutrients, thus creating a more lush plant. You’ll also need to water the plant less often since vermiculite holds water and releases it when it’s due.
grass sowing
After applying seed to your lawn, spread about a quarter inch of vermiculite over the top and water with a gentle spray. you should use about 3 cubic feet of vermiculite for every 100 square feet of lawn. This addition will increase the rate at which your seeds germinate and increase the number of seeds that germinate, for a fuller looking lawn. vermiculite will help keep a lawn consistently moist and will also protect the seeds from heat.
cut flowers
If you like to create your own homegrown cut flower bouquets, vermiculite offers a great trick to use in place of a vase filled with water. just fill your container with vermiculite and moisten with water, then add your cut flowers. this eliminates the need to change standing water, will prevent potential spills, and will keep flowers fresh longer.
bulb and root storage
For plants that must overwinter indoors, vermiculite offers an easy storage solution that will keep bulbs or root systems in top condition. First, allow the bulbs or roots to dry for several hours after removing them from the soil. then fill a container with vermiculite and place the bulb or roots. the vermiculite will prevent rotting, which is a common problem for bulbs in storage. it has wicking properties that will keep excess moisture away from the plant without robbing any of the plant’s stored moisture.
plant transplant
Whether you grew your own plants from seed or bought them from the nursery, you’ll need to transplant them into their permanent home in the ground. vermiculite will help your plant adapt better, ensuring its ideal care needs are met.
To use for transplanting, dig a hole several inches larger than the plant’s current root system and add a mixture of vermiculite and topsoil. set the root ball in place, then fill the hole with more vermiculite and topsoil. this will help control moisture levels and improve aeration around the roots, allowing for more root spread.
mulch
Vermiculite can be used effectively as a mulch for some types of plants, including roses and tomato plants. add just a few inches above ground to improve moisture control and provide heat protection to root systems.
how to use vermiculite in hydroponics
Vermiculite can be used effectively in a number of ways in hydroponics, essentially soilless gardening. Although hydroponic gardeners don’t use soil, they often use other materials to support the growth of their plants. Vermiculite can be used in place of soil in various settings, including germinating seeds or when rooting cuttings. promotes faster root growth and helps control moisture levels.
Moisture control is especially important for young plants, which have weaker root systems, which more easily succumb to rot. Vermiculite helps prevent this problem as it retains moisture, which is released when the roots need it, meaning you won’t have to be as vigilant about watering seedlings or cuttings. when used alone, you’ll need to add fertilizer to the vermiculite to provide the plants with nutrients they would normally draw from the soil.
Vermiculite can help plants more easily absorb nutrients, including magnesium, calcium, and potassium. It can also be combined with materials other than soil, such as perlite and pumice, to create custom hydroponic growing media.
Is vermiculite safe?
In the past, there have been health concerns about the use of vermiculite in homes and gardens. This concern stems from a vermiculite mine in Libby, Montana, USA, which at one time was the largest producer of vermiculite on the planet. Vermiculite mined at libby was found to contain a dangerous type of asbestos, which naturally grew alongside the vermiculite, and the mine was permanently closed in 1990.
The vermiculite sold today is subject to strict industry protocols that ensure its safe use. It has no proven toxic or carcinogenic effects and does not contain any traces of asbestos or other harmful minerals. it is commonly used around the world in various forms, not only for gardening, without any negative human impact. some people may still associate vermiculite with asbestos, but this is unsubstantiated.
pros and cons of vermiculite in gardening
advantages
- impressive water retention
- sterile
- ph neutral
- aerates the soil
- improves root growth
- increases nutrient retention
- will not rot
- prevents mold and fungus
- helps root anchorage
- promotes rapid growth
- improves soil quality
- versatile
- can be used alone or in mixtures
- expensive
- some associated health problems
- not a renewable source
- can retain too much moisture
cons
how does vermiculite compare to other mineral admixtures?
vermiculite vs perlite
both are natural mineral additives that have many of the same qualities. both are used in landscaping to improve soil quality, especially helping with aeration. Perlite is known to be more effective at aerating soil than vermiculite, while vermiculite is better at retaining moisture. it has a greater potential for expansion and, therefore, is capable of retaining greater amounts of moisture.
Many gardeners combine vermiculite and perlite in custom garden mixes, as both offer benefits to growing plants. Due to its different moisture-retaining qualities, vermiculite is better suited to moisture-loving plants such as ferns that enjoy constant humidity, while perlite would be better suited to succulents and other plants that prefer a drier growing medium.
Perlite is very lightweight, which means that when used in hydroponic gardening, it will float away, rendering it unusable. It can also be difficult to use when mixed with soil, as it can float to the top of pots and spill over the rim when watered. vermiculite tends to be heavier, so it’s ideal for use in larger pots, which require some extra weight to keep them from tipping over.
vermiculite vs. pumice stone
Pumice is another lightweight mineral that can be added to gardens for the benefit of plants. it is excellent at retaining oxygen, making it an ideal additive to improve aeration in heavy or poorly drained soils.
Mixing pumice with sandy or light soils will help improve water retention, while mixing it with clay soils can help loosen the density of the soil and make it less compact. Similarly, perlite may be too light for use in hydroponic gardening. pumice stone has minimal moisture retention qualities, so if you are concerned about increasing moisture retention, then vermiculite would be a much better addition to your garden.
conclusion
Vermiculite is a versatile, natural mineral that can be used alone or mixed with other growing media to enhance plant health and growth. It helps with soil aeration and greatly improves soil quality, but where it really shines is in its ability to retain moisture, thus ensuring roots have the moisture they need and preventing over-watering. vermiculite can be expensive to purchase, but it can prove invaluable when it comes to the health of your plants.
