You can check the acidity using special indicators or simple vinegar.
Pour a small amount of vinegar onto dry soil:
- Lots of large bubbles – the soil is alkaline.
- A moderate number of medium-sized bubbles – neutral.
- No reaction – the soil is acidic.
How to Make Hydrangeas Blue
To achieve a bright blue color, the flowers must grow in acidic soil with aluminum content. To do this:
- Acidify the soil with a solution of 10 liters of water and 1 tablespoon of citric acid.
- Use additional agents such as potassium aluminum sulfate, aluminum sulfate, or colloidal sulfur.
How to Make Hydrangeas Pink
For hydrangeas to turn pink, the soil must be neutral with reduced acidity. To achieve this:
- Regularly add dolomite, chalk, or lime.
- Apply phosphorus fertilizers.
- Monitor the pH level to ensure it does not exceed 7, otherwise, the plant may stop blooming and suffer from chlorosis.