I dont have experience with ****andra, but with prolifera, after the parent leaf starts rotting away I need to feed the plants or they start to slowly get smaller. When being fed they grow quite steadily.
I suspect that you'll have to play with your conditions - tweaking things. I usually found that the wet conditions that work well for propagation need to be somewhat drier for growing the plants past the stage in the pic. Finding those exact conditions was usually a work-in-progress for me. I typically tried a few different containers / environments and transplanted the babies when quite young. When I found some that worked well, I would place more babies in that container. The older the plants got, the more robust they tended to be.
In addition, watch your temps. while it's pretty obvious that my summer temps stressed the plants, I also found that they can get pretty unhappy in the cooler HL temps that many Neps love in my winter basement.
As mentioned, feeding can help speed up growth but the inevitable mold (for me) caused problems. Everything I used caused mold & the mold melted the leaf underneath. To keep this from happening, I normally used 70% ipa and wiped the section of leaf clean where the food lay after ~3-5 days - just before mold formation but after the plant got most of the nutrients. Without feeding all of the plants I raised tended to max out around 4 inches diameter (and many never got that big) and never flowered. With feeding, plants flowered and got up to ~7" (with this size being constrained by the glass dome I used). I'd really like to try a larger container and see how big they can get in my conditions. The large flowering plant that I had was probably the most impressive dew I've ever seen - so large, so much amazing dew and then topped with the brilliantly-colored flowers with the split anthers. It was tough to not be drawn to it - a really wonderful reward for all the effort...
All the best,
You must do the thing you think you cannot do. --- Eleanor Roosevelt
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