The Dendrobium appeared on the windowsill in all its blooming splendor. There will be great disappointment if the floral spectacle is not repeated. There are two main reasons why Dendrobium species keep their flowers under wraps. We explain here what these are and how to fix the problem.
Why isn't my dendrobium blooming?
If a dendrobium does not bloom, it is usually due to overwintering that is too warm or root rot caused by waterlogging. Make sure the temperature drops by 5-6 degrees Celsius in winter and avoid watering too often to promote flowering.
Cause No. 1: Wintering too warm
Dendrobium orchids require a cold climate to induce flowers. While they like to spend the summer in the bright, warm window seat, this does not apply to the winter rest period. The required temperature reduction depends on the respective species. How to do it correctly:
- 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 reduction in temperatures of 5 to 6 degrees Celsius is necessary for your dendrobium to bloom again. This means that you water the orchid little by little from October until the first buds develop.
Cause No. 2: Root rot due to waterlogging
When caring for orchids, the water requirement is often misjudged. Because of their tropical origins, hobby gardeners mistakenly assume 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 supplying water and nutrients. The orchid sees no prospect of successful reproduction, so it refuses to bloom.
By immediately repotting the affected orchid in dry pine bark substrate (€4.00 on Amazon), the problem can be resolved. Take this opportunity to cut out any rotten, soft roots. Then wait 8 to 10 days before watering the next time.
Tip
If you cut off green bulbs, leaves and aerial roots from your dendrobium, you shouldn't be surprised if the orchid doesn't bloom. As long as the plant parts are green and vital, they fulfill important tasks for growth and flowering. Cutting them off is only permitted when they have completely retracted and died.
