What is the difference between vermiculite and perlite?

What is the difference between vermiculite and perlite?Vermiculite and perlite are becoming increasingly popular for use in horticulture. Sowing, cutting and propagation businesses increasingly add these substances to the (potting) compost to ensure a better, more airy structure. But what is the difference between vermiculite and perlite? Our specialist explains this in this article.

What is vermiculite?

Vermiculite is a mineral that exfoliates (expands) like a harmonica when heated. This creates a very light grain with a large capacity to retain water and moist. Because of this property, vermiculite is a popular choice as (an additive to) a substrate in sowing, cutting and propagation businesses in the horticultural sector. This water and moist retaining capacity ensures that, on the one hand, irrigation water is retained, thus significantly reducing the drainage of nutrients in the process and, on the other, that the soil structure remains airy and oxygen-rich, so that plants can easily grow roots. Furthermore, vermiculite is often used as a cover layer to allow seeds to germinate, or as a propagation medium for bulbs.

Vermiculite is available in different grain sizes:
Vermiculite 1: 0 - 1.5 mm
Vermiculite 2: 0 - 3 mm This is used for covering flower seed, to promote the germination of the seeds.
Vermiculite 3: 0 - 5 mm This is used for covering vegetable seeds and for mixing in potting compost.
Vermiculite 4: 0 - 10 mm This is used in bulb propagation during packaging.

What is perlite?

Perlite is an inorganic rock which expands into a porous, airy and lightweight grain when heated. It is widely used as an additive in potting composts, cutting soils, sowing soils and plugs. As an additive in potting compost, perlite provides a lighter substrate and improved water drainage and is, therefore, often used in combination with plants that need soil that is not too moist, such as the poinsettia. Perlite is also available in different grain sizes:
Perlite 1: 0 - 1.0 mm Generally not used in horticulture.
Perlite 2: 0 - 3.0 mm Used in sowing and cutting soils, purely as a substrate and, in some cases, as a light reflecting agent for carnation and lathyrus.
Perlite 3: 0 - 6.5 mm Used to mix with potting compost for a more airy structure. 

In addition, perlite is available in substrate mats, which can be used as a substrate in various greenhouse crops. Because perlite is well-suited for steaming, the substrate mats can be used for several years.
Specialist

Questions about the difference between vermiculite and perlite
If you have questions about the difference between vermiculite and perlite, or if would you like customised advice on their applications, please contact Martin Meuldijk, our product specialist, or ask your question by completing the form below. 

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