Why does my fiddle leaf always get dark black dry edges?

@Paw14 It's an indication of a root problem, most likely related to over-watering or a high level of dissolved solids (salts) in the grow medium. If you provide answers to the following questions, it will help to determine the cause underlying the symptoms.
* How long have you had the plant?
* Does the pot have a drain hole?
* How do you determine when it's time to water?
* If the planting has a drain hole and a collection saucer, do you water such that the entire soil column is saturated and at least 20% of the water used flows through the soil into the collection saucer?
* If 'yes' to the question immediately above, do you then allow the plant to absorb the water that collects in the saucer?
* What do you use for fertilizer? What are the NPK %s?
* Does your home make use of an ionic exchange water softening system (uses salt as the exchange medium).

Al

@drdawg

In my experience, this is due to the plant being root-bound, perhaps underwatering, and/or low humidity.

I would need a lot more information on how and where the plant is being grown to narrow the scope of the possible problems. Fiddle Leaf Ficus are very easy to grow, but being a tropical plant, they do need basic care suitable for most tropicals.