For a tire that size, have them filled. Troubles end. I had that problem on the lawn tractor for years down here with all the Mesquite trees around. Couldn't keep air in the tires from one mowing to the next. Tubes made it worse. Forget patching, you'd be breaking-down the tires every hour. I had so many plugs in the tires after one year, the ride was lumpy. Bought new tires and had them filled with urethane.