Manutec | ALUM 2.5kg

Manutec Aluminium Sulphate (ALUM) is used to acidify the soil under hydrangeas whose flowers must be blue. The blue colour is induced by aluminium compound and aluminium ion will be taken up by plants only under acidic conditions.

Because the soil pH determines the colour of sepals, it is important that the pH of the soil or potting media is determined and adjusted prior to the growing period. Any pH between 5.5 and 6.0 is acceptable during plant growth, but when forcing begins the soil pH for a crop of blue sepals must be 5.5 or lower.

Directions:
Dissolve 30 grams (2 heaped tablespoons) in each 5 litres of water and apply over 5 square metres of soil, or to the soil surrounding four full size hydrangeas. Commence applying immediately after winter pruning, repeat every 2 weeks until flowering is finished.

2.5kg bag.

Analysis:
Aluminium (Al) present as Sulphate 8.7%w/w
Sulphur (S) present as Sulphates 15.5%w/w

You can quickly lower the pH of soil by adding Manutec Sulphur.

Don’t know the pH of your soil? Use a Soil pH Test Kit for an accurate and easy answer.