How to

Buy stuff. The scale is quite big, so we just combine artificial plants and flexible vines, some wood and perhaps bark and cork. Start a search like this in your browser: "plant gras fish tank artificial blue" (also try "purple" & "pink"). Check search results and order the plants you like. If you are lucky, you may even find fluorescent  plants in matching colours: highly recommended! Studying pictures from the movie helps to get a feeling for the look. If you happen to find a textile Sarracenia (trumpet pitcher plant): congrats! This species looks incredibly alien and perfectly matches with the idea. Note: beneath black light white turns to bright blue. Blue and purple mostly keep their colour. Green (if not fluorescent) often turns to black - but sometimes not. Concerning colour, semi-transparent material seems to perform best. If you shop in the real world, you might provide yourself with a little uv torch light to check the effects. People might stare at you, but you're on a mission...

The eyecatcher - even not dedicated fans of Avatar often associate this item with the movie / recognise it at once! I found no way to craft this by myself, so I simply ordered one "Avatar Avatar Sacred Tree Seed Light Pandora Seed Of Life light" (play with search terms), offered for very little money by various vendors. Recycle or donate to your local maker space electronic components and just keep the wobbly silicone umbrella. Plug onto a small LED diode provided by a common LED string light. I recommend the colour blue.  You might need to stabilize it with a barbecue stick or anything else you find suitable.

I like the extaterrestrial fungi in the Na'vi River Journey set up. Take a look at DIY Glowing Mushrooms Skyrim Art by Meeka and alter her very simple how-to according to your imagination. Mold cone-shaped matrixes from putty clay and let dry. Continue as described in Meeka's video (isolate with clingfilm, cover with a thin layer of transparent silicone, cover again with clingfilm and carefully even out the surface. Let dry off and peel of both layers of clingfilm). Note: Use a (very small) amount of fluorescent acrylic paint to colorize the transparent silicone. I mixed some blue with green. Plug fungi hats onto small LED diodes provided by a common LED string light on a piece of bark as explained in Meeka's Video. The diode might shine too bright, therefore you can stuff the fungi's heads from within with a small amount of fluorescent putty clay (in this case yellow). Our fish tank plants often come with tiny roots at their basements - sometimes fluorescent. If included at the fungi's basements, this adds a nice effect.