As soil pH determines sepal colour in hydrangeas, it is most important that pH of the soil or potting media is determined and adjusted prior to the growing period. pH can be lowered by adding sulphur to the media and maintained by the regular use of this solution. Follow package instructions for the best outcome.
nitrogen 23 %w/w phosphorus 1.9% potassium 19.5% sulphur 0.18% Magnesium 0.1%w/w iron 0.05%w/w manganese 0.03% w/w zinc 0.01%w/w zinc 0.01% w/w copper 0.01% w/w boron 0.005% w/wmolybdenum 0.001%w/w Nitrogen to Phosphorus (N:P) ratio 11.5:1
aluminum 8.1%w/w sulphur 14.4%w/w