Frequently asked questions about perlite

Perlite is a natural volcanic glass that is heated suddenly to around 850–1200 °C and expands to roughly ten times its volume. The result is a white, porous and very light granulate that makes potting soil loose and airy.

Both are correct and mean the same material. “Perlit” is the German spelling, while “perlite” is the international form that is also standard in the trade.

Fine perlite (approx. 0–3 mm) suits sowing and seed-starting compost, medium (approx. 2–6 mm) suits most uses from houseplants to raised beds, coarse (approx. 4–8 mm) suits coarse, airy mixes and drainage. If in doubt, medium is the most versatile.

No. Perlite is practically nutrient-free, pH-neutral (typically 6.5–8.0) and has a very low cation exchange capacity. It only improves the structure of the soil; fertilising and pH are up to you.

For most houseplants and balcony plants 10–30%, as a rule of thumb 1 part perlite to 4 parts soil (20%). Seed-starting compost tolerates 20–30%, cacti and succulents 30–50% mineral content, and cuttings will even root in pure perlite. All figures are in the guide How to mix perlite.

Yes, for cuttings and in hydroponics. Because perlite contains no nutrients, plants in pure perlite need a nutrient solution or regular feeding from the start. For long-term pot culture, a mix with soil or coco is easier.

It depends on the goal: perlite mainly provides air and drainage, while vermiculite stores far more water and nutrients. Against waterlogging and for airy soil, perlite is the better choice; for evenly moist sowings, vermiculite can suit. More in the comparison.

Yes. Heavy clay soils can be loosened with about 10 litres of perlite per m²; when renovating a lawn, rake in 5–10 litres per m² after scarifying. In a raised bed, around 20% in the top layer is enough.

Yes. Perlite does not rot. Remove root remnants, rinse it thoroughly in a sieve and let it dry. After diseased or infested plants, pour boiling water over it first.

Send us an enquiry via the contact form or by email to info@acar-gartenbedarf.ch. You receive a no-obligation quote; once you have confirmed, we agree with you how you will receive your perlite. There is no online shop with a shopping basket.

You receive the price with your personal quote, depending on grain size, quantity and delivery.

According to safety data sheets, perlite is not classified as a hazardous substance. Like any fine mineral dust, however, perlite dust can irritate the eyes and airways. Perlite is not intended to be eaten.

Dampen perlite before use (a few litres of water for a large bag), work outdoors or with good ventilation and pour from a low height. For larger quantities or indoors, a dust mask with a P2 or FFP2 particle filter protects you.

In part. Perlite is a natural, long-lasting and reusable rock and helps you mix peat-free soils. However, it is open-cast mined, is not renewable, and expanding it at over 850 °C takes energy. Industry figures put it at around 0.5 kg CO₂ equivalents per kilogram of expanded perlite.

In Switzerland yes, as a substrate component: the FiBL 2026 inputs list includes perlite among the mineral substances allowed in substrates, provided the material has not been treated after extraction. Our perlite is not a certified organic product; in case of doubt your organic certification body has the final say.

Small amounts can be worked into garden soil or compost – perlite is an inert mineral. Dispose of larger amounts according to your municipality’s rules.