Season the pork shoulder roast in a large bowl prior to placing it in the slow cooker. Mix ½ of a slow cooker seasoning pack with ½ cup of water and pour it into the slow cooker. Rub the rest of the seasoning packet onto the road.
Add seasoned water and roast to the slow cooker.
Peel a sweet potato and a yam and cut into large chunks. Place in the slow cooker with the roast.
Cut ½ large white onion into chunks and add to the slow cooker as well.