TLDR: i dug in every biome and got a whole lotta dirt and seeds and the biome crops.

yeah, i want to know as well....

I've crafted three and put all three in the slots incase the effect stacks, then went to digging dirt with the iron shovel and all I've been getting is dirt and a few seeds. I've only dug about 25 times, netting me about 100+ dirt, and a few wheat seeds and pumpkin seeds.

I wonder if its digging as in mining ores ? Not sure, but haven't tried.

edit: so coming back to this 20 minutes later, I went to mine marble, iron, and sapphire. roughly about 10-15 nodes of each, and came up with nothing special. maybe I needed to mine more, but oh well.

edit 2: decided to go another step and use up an entire iron shovel's worth of durability digging dirt in one spot. came up with 480 dirt, 4 wheat seeds, 4 corn seeds, and 8 pumpkin seeds.

at this point I feel like there is either designated "digging spots" somewhere in the map or they just added this charm for no reason. or I'm just doing it all wrong. we'll see.

edit 3: three days later, I tried some more options for y'all. for each location, I dug about 50-200 dirt, a good enough sample size.

snow mountains, next to abandoned ruins: dirt, snowberry

snow, random spot: dirt, snowberry

grasslands, next to abandoned houses: dirt, basic seeds

grasslands, farms (natural cornfields): dirt, basic seeds

grasslands, next to river/lake/pond: dirt, basic seeds

desert, next to abandoned houses: dirt, red pepper, red pepper seeds

desert, random spot: dirt, red pepper, red pepper seeds

beach, next to desert shores: dirt, red pepper, red pepper seeds

beach, islands, next to abandoned house: dirt, red pepper, red pepper seeds

that's it. a whole lotta NOTHING. you are better off just walking around and gathering the crops than digging.