Heap of expanded perlite in white grains, fine to medium grade, on a white background

5 L bag of VG Garden perlite, white grains visible through the transparent packaging, growing medium

Expanded perlite for grow medium and seedlings, 5 L

Name: Expanded perlite for grow medium and seedlings, 5 L
Price: 5.9 EUR
Availability: InStock

5,90 €

Perlite is an expanded volcanic rock, light and free-draining, that keeps air around the roots in potting compost, coconut fibre or vermiculite, even when wet and compacted. It is sold in 5-litre bags and is used in aquaponics, in hydroponics and in the garden alike.

Growing medium

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The summary

What you receive: 5 litres of perlite, a volcanic rock expanded at 1,200 °C.
What it does: it keeps air in a mix, even when wet and compacted.
How to use it: as an addition to potting compost, coco fibre or vermiculite.
How it arrives: a 5-litre bag, very light, shipped with the rest of your order.

Expanded volcanic rock that keeps air in a grow medium that tends to compact

Expanded perlite for grow medium and seedlings, in a 5 litre bag, is a volcanic rock heated to around 1,200 °C that keeps air around the roots, even in a wet, compacted mix. Added to potting compost, coco fibre or vermiculite, it acts as a soil conditioner and supplies no nutrients.

Perlite is a volcanic rock heated to around 1,200 °C: the water it contains turns to steam and makes it pop into white, light, porous grains. Added to your compost, your coir or your vermiculite, it keeps air spaces between the particles, even when the mix is wet and compacted. The 5-litre bag carries the NF U 44-551 standard, which governs growing media in France.

🫧 The air left in the mix

In your pots, the roots breathe through the spaces that the water leaves free between the particles. A fine potting compost settles with each watering, those spaces close up, and the root ends up in a saturated medium where oxygen is lacking. The rigid perlite grains keep these voids open and let excess water drain towards the bottom, so that your mix stays moist without becoming waterlogged. As the material is mineral, it does not break down and keeps this structure from one crop to the next.

It keeps its shape

A grain keeps its volume under the weight of wet grow medium, and the air space with it.

It does not break down

No decomposition takes place over the months: the mix keeps the structure it had on day one.

It adds nothing

The material is inert: your fertiliser remains the only source of nutrients for the plant.

🥄 The right proportion

Your dose depends on the problem you are correcting. A heavy compost that is still soggy 2 days after watering needs more perlite than a mix that dries quickly. To lighten a potting compost, 1 part perlite to 3 parts compost is a common ratio: a 5-litre bag mixed into 15 litres of compost therefore makes 20 litres of mix. The fine to medium grade of this bag mixes in by hand, without tools, and spreads evenly through the compost. Poured dry, it gives off a fine dust that irritates the eyes and airways: dampen it lightly before opening the bag fully and pouring it.

Pure, and in a water circuit

A bag of perlite does not fill a pot. Used on its own, it holds little water and no nutrients, and your plant then depends entirely on how often you water. It also floats, and in a flood-and-drain bed or a float tray the grains rise at every cycle until they spill over the edge. Keep it for potting mixes and seed trays.

The grow medium it is meant to correct

For your seedlings and young plants, the light peat-free compost makes a ready-to-use base, to which you add perlite if it stays too wet under your watering conditions. For filling larger pots, compressed coir rehydrates in about half an hour and is lightened in the same way. In both cases, perlite corrects the structure of a mix you already know, which saves you from making one up from scratch.

🌱 From seedling to water circuit

Combined with vermiculite, which stores water while perlite lets air through, it makes a seedling grow medium that holds moisture without suffocating the young root. The same pairing is already blended in the coco fibre with perlite. In your aquaponic system, perlite is used mainly at this stage: the seedling comes up in a pot of aerated mix, then moves on to a bed of clay pebbles, which do not float and withstand flooding. The guide to choosing a grow medium in aquaponics compares the materials for a grow bed, with clay pebbles at the top.

Technical specifications

The essentials

Volume: 5 LVery light bag, ready to mix with no preparation.
Origin: Expanded volcanic rockHeated to 1,200 °C until it pops into white grains.
Particle size: Fine to mediumMixes by hand, without tools, and spreads evenly.
Behaviour: Inert and rigidNo degradation over the months, and no element released into the solution.

To budget for separately

A supportive grow medium: Potting compost, coir or vermiculitePerlite improves a mix, but it cannot make up a mix on its own.
Fertilisation: A complete fertiliserThe material is inert: nothing comes from it.

In the box

1 bag of expanded perlite, 5 litres

Volume, mineral origin, expansion temperature and particle size recorded on 19/09/2026 from the product description; standard NF U 44-551 printed on the bag.

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A 5-litre bag of perlite weighs very little but takes up the volume of a whole parcel: it is the bulk that determines the price. The exact costs are shown in your basket once you have entered your address.

Frequently asked questions

6 questions

6 key questions

Can you grow in pure perlite?

What proportion should be added to potting compost?

Does perlite float in a flood-and-drain bed?

Perlite or clay pebbles for draining a pot?

Point	Perlite	Clay pebbles
Where it works	within the mix	at the bottom of the pot
Weight	very light	heavy and stable
Floats	yes	no

The clay pebbles form a drainage layer beneath the grow medium; perlite, for its part, works inside the grow medium.

Can it be reused from one crop to the next?

Does perlite change the pH or conductivity of my solution?

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Expanded perlite for grow medium and seedlings, 5 L

The summary