Tortuga is rife with dig spots (which can make it difficult to find the right one). Without even going into the jungle we have:
- In front of Hendry Cutts, the woodcutter
- Hendry's pig pen
- Between the jail and Misty Mire entrance
- The grassy hill across from Fabiola
- The grassy slope near Butcher Brown
- The area outside the town walls, directly behind the Faithful Bride Tavern
That last one proved to be the most beneficial to me, holding the items for several of the quests. YMMV.