When Al is present in the sepals, it binds with this pigment and co-pigments, caffeoylquinic acids, to results in blue sepals. If aluminum is not present, plants can't absorb enough to form the blue pigment complex high N levels, 30-50 ppm in the soil solution. This antagonizes the uptake of Al high P levels, 6-12 ppm in the soil solution. Phosphorus also antagonized Al uptake low K levels, 10-20 ppm in the soil solution. Use 3-5 oz.
Hydrangeas have a high demand for water, and no other plant is as unforgiving of wilt.
Light levels should be between 5,000 - 7,000 f.c. Night temperatures should not fall below 70F for extended periods to prevent premature inflorescence initiation. Pinching is done to produce multiple inflorescences per plant. For multiple inflorescences, 2-3 wks after potting the cutting, pinch leaving 2 nodes per shoot. If a second pinch is made, allow the shoots arising from the first pinch to develop so that each will have 2 nodes remaining.