Been there done that. Three to four weeks before running on it. If you push too soon the dog could break it open again and you would be back to square one.
See what your vet says and then add a week or so to that unless the vet fully understands that your dog is a field dog. I have my vet say I could resume "normal" activities 3 days after he trimmed Deuce's toenail down to a bloody nub when he shattered it last spring. We went out to train after 4 days with the nub well scabbed over.... needless to say after one retrieve at full speed (this dog doesn't know slow) the toe nail was bleeding profusely.
While it is healing fully think about getting some protective dog boots. Put some gauze over the wound, then vet wrap, then slide the foot into the dog boot. Take some video of you dog as they get used to wearing the boot because it is hilarious to watch them walk until they get used to the feeling of wearing a boot.
GMHRCH-III WR North Star's Deuce of Diamonds
MHR WR Pondview's Bar None 1994-2006