This is beyond the scope of an answer that can be provided here. The short answer is you use PHP (generally) and when someone clicks "lemon balm" it passes the database record ID. This is then used to pull the record from the database and fill the page with data from the record.
You say you don't want an individual page for each herb, but you are ...
This answer is about PostgreSQL, but I guess it should be the same for MySQL as well.
Step 1 - see your DB Storage Size (read more about converting GiB to MB here)
Step 2 - see your DB Free Storage Space
Clicking the monitoring cube will give you a more exact number:
Step 3 - Subtract the Free Storage Space from the Storage Space
Should be pretty easy.