The vast majority of plants benefit from better aeration around the root zone. Many substrates can become a bit boggy and the regular watering can compact it. By adding Vermiculite to help improve aeration by increasing air content. It will also assist with nutrient retention as it has a better water holding capacity than perlite. Lots of soils come with perlite, usually at a rate of about 5% but many watering systems such as Autopot perform better with more. A ratio of 60/40 is often a good mix and Vermiculite is a great way to get it.
So what actually is Vermiculite?
According to Wikipedia “Vermiculite is a hydrous phyllosilicate mineral. It undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently, and the effect is routinely produced in commercial furnaces. It is formed by weathering or hydrothermal alteration of biotite or phlogopite.” Translated into english, it is a kind of rock that undergoes super heating to make it expand. So it ends up looking a little like metallic puff pastry!! It is these thin layers of mineral that retain the water and air that makes it so effective. Being mineral, it will not rot, deteriorate or mould and is enduring, odourless, non-toxic and sterile. Depending on the original source, it is generally pH neutral at around 7.0.
What are the alternatives to Vermiculite?
While Vermiculite is a great aerator and water retainer, many people opt for perlite instead. Perlite doesn’t hold as much water as Vermiculite but is better for aeration. It is a bit of a toss up, depending on what you want. To see what other soil mixers we have, please click on this link.