The stem is a 2-way street. Roots send water/nutrients up, and the top sends a keiki inhibiting hormone down. When plant gets tall enough, the hormone no longer reaches the base of the stem, and then keikis start to form.

In this case, try to keep it together till roots above the break are well established. Then cut the top off and plant separately.

Whether base will give you a keiki is unknown. Depends in part on how much hormone is getting through now, in part on whether lower part of stem has any leaves, and in part on who knows what. In a vacuum, in this case it is probably 50/50 whether base will produce new growth.

While on the topic. I have a Vanda coerulea var. supra... I have a six inch kieki below an area I had to top last year due to suspected rot. The whole plant is about two feet tall with decent roots. I've been waiting and waiting for the kieki to develop roots, but it keeps growing... But still no roots? What could I do to promote new roots. I grow in lava rock in a pot, with bright light and intermediate temperatures.


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On Vandas it can take a long time for keikis to form their own roots. I am not aware of anything we can do to get roots going.

*Update*
 

Here is my Vanda about a month later with 12 more roots above the beak on front and back of the plant. The flower stem it still has is going strong after about 3 months and I just noticed today a new spike. Are the roots long enough now?