It's Wednesday which means its time our weekly look at my understanding of a horticultural word. This week we are looking at perlite.


Perlite is a naturally found volcanic glass that can be used in the garden but is commonly found in ready-made compost mixes. It is often noted to look like styrofoam however under a microscope it looks very different. If you have ever bought a plug plant from a garden centre, you have probably noticed little white balls. That is what we are talking about here.

Because perlite is light yet very porous, it is often added to potting mixes as a way of improving drainage while holding on to moisture and nutrients to help a plant grow. It can also improve aeration which allows more air to plant roots and worms, reducing waterlogging. Its rough shape means that it catches water and nutrients in all its cracks and crevices while its porous nature acts as a filter allowing for improved drainage.

We could add this to raised beds, pots or even garden soil to improve plant growth by improving drainage and water retention. The ratio I normally use is about 1 to 3.

I've added perlite to compost in order to improve both drainage and water/ nutrient retention. This improved my germination rate significantly. Generally, I add a scoop of perlite to 3 scoops of seed compost.

I have also covered seeds in a layer of perlite instead of compost before. Because of how light perlite is, seedlings can find it easy to push through the top and start there growth.

We can purchase perlite from a local garden centre or alternatively from Amazon by clicking on the following image

Do you use this wonderful ingredient in your garden? How do you use it? Or do you plan to use it in order to improve germination? If any of this applies to you let me know in the comments below.

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