The Dendrobium found its way onto the windowsill in all its bloom. The disappointment is great when the floral spectacle is not repeated. There are primarily 2 reasons that cause Dendrobium species to keep their flowers under wraps. Here we explain what they are and how to fix the problem.
Too much moisture can prevent flowering
Cause No. 1: Overwintering too warm
Dendrobium orchids need a cold-blooded climate for their flowering induction. While they like to spend the summer at the bright, warm window seat, this does not apply to the winter rest period. The required temperature drop depends on the species. Here's how to do it right:
- Dendrobium phalaenopsis: in summer 20 to 28 degrees Celsius - in winter 12 to 18 degrees Celsius
- Dendrobium nobile: in summer 15 to 28 degrees Celsius - in winter 5 to 13 degrees Celsius
As a rule of thumb, a drop in temperature of 5 to 6 degrees Celsius is required for your Dendrobium to flower again. This means that you water the orchid in sips from October until the first buds develop.
Cause #2: Root rot due to waterlogging
When caring for orchids, the water requirement is often misjudged. From their tropical origins, hobby gardeners mistakenly conclude that the rainforest flowers need to be watered regularly. In fact, the substrate with the aerial roots should only be kept slightly moist and should almost dry out in the meantime.
Watering too intensively causes waterlogging and root rot on Dendrobium. As a result, the root strands soften and stop the water and nutrient supply. The orchid sees no prospects of successful reproduction, so it refuses to flower.
The problem can be solved by immediately repotting the affected orchid in dry pine bark substrate. Take this opportunity to cut out any rotten, soft roots. Then wait 8 to 10 days before watering the next time.
tips
Anyone who cuts off green bulbs, leaves and aerial roots on their Dendrobium should not be surprised if the orchid does not bloom. As long as the parts of the plant are green and vital, they fulfill important tasks for growth and the willingness to flower. Cutting is only allowed when they are fully retracted and dead.