I would rely on tested and trusted products like the ones mentioned. They do have other nutrients and micro-minerals that are beneficial to the plants rather than just one single vitamin.
Nothing wrong with home remedies, but it doesn't work for everyone since we all grow in different conditions. I tried the warm water + sugar bath before, it ended up in a huge mess of fungus problem. After that, I revert back to the trusted products and my plants and I are both happy. Just my
!