Why Perlite Matters in Garden Media
Perlite is expanded volcanic glass that increases air porosity while keeping mixes lightweight. Many container blends target 10–30% perlite by volume, while seed mixes often use 30–50% to protect fine roots. Fast-draining cactus blends commonly reach 30–60%, especially in humid climates where soggy media can trigger root rot.
Typical Percentages and Practical Targets
If you already know your total mix volume, multiply it by your chosen perlite percentage. For example, a 40 L batch at 20% needs 8 L before allowances. Adding 5% waste raises that to 8.4 L. For 60 L at 40%, the base is 24 L and the 5% allowance becomes 25.2 L.
Measuring Beds, Pots, and Batches
When you only have dimensions, the calculator converts to liters using 1,000 cm³ = 1 L. A 120×60×20 cm bed holds 144,000 cm³, or 144 L. At 10% perlite plus 5% waste, that becomes 15.12 L. For round pots, volume is π×r²×depth, so a 30 cm diameter pot filled 25 cm deep is about 17.7 L.
Bag Planning, Cost, and Transport
Bag sizes vary widely: 10 L, 25 L, and 100 L are common. The calculator rounds up using ceiling math, so you never under-buy. If 25.2 L is needed and bags are 10 L, you should buy 3 bags. With a cost of 450 per bag, your estimate becomes 1,350 in your selected currency.
Weight Estimation and Handling
Loose perlite is light, often around 0.07–0.14 kg/L depending on grade and moisture. At 0.09 kg/L, 25.2 L weighs roughly 2.27 kg. Weight estimates help when you are carrying bags upstairs, arranging deliveries, or comparing shipping charges across suppliers for you.