Hydrated Lime For Mushroom Substrate Pasteurisation

Unlock professional-grade results in your mushroom cultivation with our Hydrated Lime (Calcium Hydroxide). Also known as builders lime, Hydrated Lime is a vital tool for cultivators who want to streamline their workflow using "cold water pasteurisation," a highly effective low-tech method that bypasses the need for energy-intensive heat or steam.

The Science of Cold Pasteurisation Using Hydrated Lime

When added to water, Hydrated Lime works by rapidly increasing the pH level to 12 or higher. This dramatic alkaline shift creates a hostile environment for competing moulds and bacteria that could otherwise ruin your crop. This chemical pasteurisation process using Hydrated Lime effectively "cleans" your substrate—such as straw, sugarcane bagasse, or chopped corn stalks—while keeping the physical structure of the cellulose intact. This ensures that when you introduce your mushroom spawn, the mycelium has a clear uncontaminated path for rapid colonization.

Versatile and Easy to Use

Using Hydrated Lime is one of the most accessible methods for beginners and commercial growers alike. Simply soak your substrate in a lime-water solution (typically for 12 to 24 hours) to achieve the necessary pastuerisation level. Once drained, the pH will naturally begin to stabilise, allowing your oyster mushrooms or other wood-loving species to thrive without the risk of "green mould" (Trichoderma) or other common pathogens.

Benefits for Your Grow:

• Energy Efficiency: Save on electricity or gas costs by using a no-heat pasteurisation technique.
• Pathogen Control: High pH levels effectively eliminate harmful microbes that compete for nutrients.
• Substrate Compatibility: Perfect for cellulose-rich materials like straw, bagasse, and cardboard.
• Consistency: Provides a reliable and repeatable method for large-scale mushroom production.

By integrating Hydrated Lime into your cultivation process, you are choosing a proven, sustainable, and cost-effective way to ensure healthy flushes and high-yield harvests every time.

Works well for pasteurising oyster mushroom substrate supplementing with fresh coffee grounds or even up to 30% soy hull supplementation.

1 - Chop and pre-soak your substrate material (e.g., straw or bagasse).
2- Mix hydrated lime into clean water at a rate of approximately 1 gram per litre (adjust slightly based on your local water pH).
3- Fully submerge the substrate in the lime water solution for 12–24 hours, ensuring it’s weighed down to stay below the surface.
4- Drain thoroughly—do not rinse—then pack the substrate into grow bags or containers and inoculate with mushroom spawn.

This method is especially popular for growing oyster and other fast-colonising species that thrive on high-pH treated substrates.

250g – Ideal for trials or hobby setups, treat up to 250L of water
500g – Small batch growing, treat up to 500L of water
1KG & 2KG – Great for ongoing or commercial use, treat between 1000-2000L of water

• We ship from Tamborine Mountain, QLD using either AusPost or Aramex
• Fast dispatch within 1 business day (excluding Fridays) with express post options available