The bulb that you have growing in the water gel looks very happy. This might be a good method to curb the diseases that cause bulb rot, since the bulb itself is not covered in wet soil.. Are you seeing any fungus gnats around the containor? If you aren't, this might be a real breakthrough in the elimination of that problem. I guess if there is a concern that the roots are heating up too much, just tape a piece of paper around the jar. Are the slugs eating the leaves on your outside Amaryllis? With no rain this spring, the slugs haven't been much of a problem for me.
