I need help on how to grow my mophead hydrangeas
I have put my hydrangeas in a soilless medium. I mean a mixture of coco peat, sand in 4:1 ratio but cocopeat is supposed to be rich in nitrogen. You said that too much of nitrogen promotes only lush green growth with little flowers. Suggest to me what I should do? Should I repot the hydrangeas into normal fertile soil amended with some compost or continue growing it in the same pot by adding bone meal to increase phosphate content of the soil?
Your potting medium is not rich enough to grow hydrangeas, Cocopeat and sand is used to keep the soil open and airy so it drains wel, but doesn't contain enough nutrition. Ammend your mix with organic matter like spagnum peat moss, pine bark and compost. Cocopeat should be no more than a of a quarter of your growing mix. Fertilize lightly every other week with a balanced plant food, formulated for acid loving plants.