My hibiscus wine recipe says to ferment to dryness before racking to the secondary carboy. It's been almost a month, and the bubbling has died down. Is it time to rack?
Depending on the fermentation temperature etc. then fermentation will take a different amount of time.
On average all of the wine I make ferments out to around 12% dry in around 5/7 days. If you have left it a month then I'm sure it will be done by now. Unless there has been any problems with the fermentation pausing.
Get yourself a hydrometer from a homebrew shop or online and measure the sugar content.
After a month it's more than likely fermented out. The way to know for sure is to take a sample using a wine thief and check the gravity using a hydrometer. If it's around 0.995 then the wine has completed fermenting. But if you don't have the equipment, then racking now to secondary should be fine.
I would if it were me. In fact when I use fresh grape juice anymore I transfer after just 3 to 5 days then again 2 weeks later. If you intend to bulk age at some point be sure to top the carboy up to the neck and if you're ok with Sulphites use 1/4 teaspoon of Potassium metabisulfite per 5 gallons to reduce risk of wild yeasts.