If the name doesn't sound familiar, chances are you probably came across it at some point. In appearance, it looks like a mixture of gold flakes and sawdust and it plays important role in soil mix - both when sowing seeds and when growing certain potted plants.
What is it?
Web description of vermiculite is that it is a porous, heat-treated mineral that is used in a number of different areas - construction, ventilation and cultivation for example. If you ask a plant enthusiast, they will instead say that vermiculite is a soil improver used in the planting of certain seeds and plants - in a nutshell. It has a fantastic moisture-retaining property which means that the soil never dries up if it is mixed into the soil.
Another good thing about vermiculite is that it creates an insulating layer. The top layer of soil is thus kept moist for a long period, at the same time as light is let through. Perfect for seeds planting that are not allowed to dry out under any circumstances, at the same time needing a larger amount of light to start germinating. The material is also sterile, which means that disease or vermin can not keep up with just the speed. An extremely good product for plants that want to stand with their roots soaked in other words!
Which plants Vermiculite suitable for?
Truly, I think it depends on what kind of plant waterer are you. If you know exactly how much water they want - it is best to skip this material in your soil if you're an over-waterer. Tropical plants that never want to dry out, on the other hand, happily accept a large portion of humectants, especially in combination with a draining material such as perlite or pumice. A few examples of water-thirsty plants are:
Ferns
Moses
Philodendrons
Calatheas
Maranthas
All other plants that are sensitive to dehydration
In addition to these plants, I personally like to sprinkle a little vermiculite over a new caudex, regardless of variety. During their first weeks/months of life, they never want to be dry out, a task that is difficult to fulfill when the sun is on and the days are hot. By covering the soil with vermiculite, you create a perfect environment that is both light and moist.
Vermiculite in a nutshell?
retains moisture & nutrients
suitable for seed germination
quite sterile material so great for indoor plants
light & airy material even when retaining water