Hydrated Lime · £/kg

Our hydrated horticultural lime, also known as calcium hydroxide, is ideal for cold water pasteurisation of straw when cultivating aggressive mushroom strains such as oyster mushrooms.

Unlike typical builders’ lime, garden lime, or dolomite lime, this specialised product contains low levels of magnesium, ensuring it doesn’t harm mushroom mycelium or lead to stunted development. We utilise this extensively in our commercial mushroom-growing operations as it provides a cost-effective method of pasteurising straw.

By raising the pH of the soak water solution to an extremely alkaline level of 11 to 13, the lime effectively kills harmful competitor organisms and spores.

For safety reasons, it is advisable to wear appropriate protective gear when handling hydrated lime, as it can cause irritation to the skin, eyes, and lungs if inhaled. Always use gloves, goggles, and a mask, and handle the substance with care.

• Water solubility of lime ranges between 1.89 to 1.73 g/L (0°C to 20°C).
• For cold soaking straw in a 50-gallon drum with 200 litres of water, approximately 350g of lime is required.
• The soak should last between 10 to 24 hours for proper pasteurisation.

During pasteurisation, the pH of the lime solution typically drops to between 6 and 8. This is normal but can vary. If the pH exceeds 8, use citric acid to neutralise the water before disposal. Additionally, wood ash can serve as an alternative pasteurisation agent or can be combined with the lime soak to provide extra nutrients to the substrate.

Please review the drop-down sections below before placing your order, especially product lead-times if stated.