Here I was thinking I was clever and sneaky with the silica knowledge! There are many ways to apply it, there are foliars but I think it has to be a particular salt or complexed somehow. Diatomaceous earth with break down over time and become usable, I have seen many soil recipes use it to help clear out an initial bug problems and long term help support silica absorption.
Stems become noticeably stiffer and more resilient. As mentioned before, having actual windy, forcible air flow pushing plants around can help make them stronger and stimulate stem growth too. I would say it really helps with tall, long flowering plants.