Let us freeze crop stages for more block variety (ideas in post)

There are many crop stages that I would love to build with in survival but can't. It would be cool if there were some ways to stop crop growth at certain stages: not even the debug stick to change their age works, since they end up aging anyway. Currently the only way to achieve this is with RandomTickSpeed permanently set to 0, which is impractical.

Ways to stop growth organically could be: having a block such as ice under farmland, having a block above it (like string, which would work well for decoration purposes), waxing them, and making the debug stick freeze them at certain stages. 

This would open so many possibilities.