Perlite - 1000 cc

Perlite 1000 cc: a moisture buffer for your grow

Perlite starts out as volcanic rock with a few percent of water locked inside it. Heat that to around 900 degrees and the water turns to steam, popping the grain open like popcorn until it is several times its original volume. What comes out are light white granules riddled with cavities and cracks. All those openings let perlite take up a serious amount of water, roughly two and a half times its own weight, and then give it back to the air little by little. The heat of production also leaves the material sterile, which helps when you are working with sterilised substrates.

In mushroom growing, perlite is mostly used to keep humidity where it needs to be. A layer of damp perlite on the floor of a fruiting chamber acts as a slow humidifier: the enormous surface area evaporates steadily, so you mist less often and the humidity holds steadier than it does with a few bursts of spray a day. Perlite also goes into substrate and potting mixes, where it keeps air between the particles and works against compaction. The material does not break down or settle, so that structure lasts the whole run.

How to use perlite in a fruiting chamber

1. Wet the perlite in a bucket of water first; dry perlite throws up dust that you would rather not breathe in.
2. Drain off the excess until the granules are damp but no longer dripping.
3. Spread a layer a few centimetres deep across the bottom of your chamber or tub.
4. Stand your grow on a rack or a small dish above the perlite so that it is not sitting in water.
5. Stir or mist the perlite when it dries out, or top it up with water, and replace it if you have any doubt about hygiene.

More growing supplies at Avalon

Work with clean hands and use a clean scoop, and the bag stays usable for the grows that follow. Keep the remainder dry and closed. The same category at Avalon Magic Plants holds autoclavable filter bags, sterile syringes with needle, sterile gloves, face masks, rice flour and a thermostat.