Yates Aluminium Sulphate Liquid is a 500mL hydrangea blueing treatment that supplies aluminium to help develop and maintain blue flowers. The liquid formulation mixes with water for application to the soil, without handling dusty powders.
Aluminium sulphate for blue hydrangeas
Flower colour depends on soil conditions. For blue hydrangeas, aim for a soil pH of 4.5–5.5. Test before treatment and at least every three months during use. Do not lower pH below this range, as this can damage plants.
Ingredient: 2.5% w/v aluminium (Al), supplied as aluminium sulphate.
Directions for use
- Dilute 20mL in 5 litres of water.
- Apply 5 litres of diluted solution over 5 m² of moist soil around the plant.
- Repeat every 3–4 weeks as required.
- Treatment can begin at any time of year, including after winter pruning.
Use smaller, repeated treatments rather than one heavy application. Yates recommends combining treatment with Yates Soil Acidifier where needed to achieve the required soil pH.
Application precautions and storage
- Apply to soil only. Immediately rinse any splashes from foliage.
- Avoid application when temperatures above 30°C are forecast, or plants are moisture-stressed.
- Apply in the early morning or late afternoon.
- Store somewhere cool and dry, out of direct sunlight and inaccessible to children and pets.
Frequently asked questions
How much diluted solution does one bottle make?
At 20mL per 5 litres, a 500mL bottle makes 125 litres of solution. This provides 125 m² of total application coverage, including repeat treatments.
Should I check soil pH before applying aluminium sulphate?
Yes. Check before starting and throughout treatment. The target range for blue flowers is pH 4.5–5.5; adding more product without checking pH risks making the soil too acidic.
Disclaimer: Always read and follow the instructions on the product packaging before use, and don't depend on information on this page that may have errors or be outdated.