- What's the best way to prepare it for planting? Each plantlet stem I have is about 10 cm long, and has 6-9 pairs of leaves, right down the bottom.
As long as you have a continuous section of stem between two sets of leaves you can plant it and it will grow. Basically you want one segment of stem between the leaf nodes. Roots will form from leaf nodes and so will new growing buds. If you cut the stem and do not include at least one continuous node then there is a chance the bit will die or take a long while to grow.0
Should I strip most of the leaves? How many should I leave on each stem?
No do not strip the leaves at all.
- How deep should I plant each stem?
Plant the stems about half an inch to 3/4ths of an inch. Basically just deep enough to ensure they don't float around the tank. It is ok if a few of the lower leaves are buried in order to keep the plant fixed in place.
- How far apart should I plant each stem?
This is not too critical, they will grow together into a thick mat. So as close as you can get them if you want them to look dense, or diffuse if you want to plant a large area and don't have a lot of stems.
- Can I chop the stems into two portions? Would both the 'top' and 'bottom' portions grow?
Yes, as long as you have one continuous node. Both parts will grow new leaves and roots.
- I'm pretty sure it's been grown emersed. Will the existing leaves die off? If so, should I trim them and how do I know when to?
If you have good lighting and CO2 then probably not, if your light and CO2 levels are low then you might get some die off. Be sure to take photos of the damaged leaves first before trimming them as it might be a deficiency.
There is also a chance that the plants will melt like crypts melt after being planted. This species tends to do that occasionally for unknown reasons. The stems will remain but the leaves will die off and regrow later. So don't worry too much about that if it happens.