Adam, the most important thing to know about the tire is if it is loaded with fluid for extra weight. I'm assuming it does not have fluid because you would have seen it coming out of the tire at the leak. If it does have fluid and the hole is wet, you may have a problem getting a plug to seal properly. The first thing to do with a plug is to ream out the hole. That kinda always rubs me the wrong way, making the hole bigger before I fix it. Also, is the leak on a lug or in the valley between lugs? I think if it were mine and did not have fluid in the tire, I'd go down to Walmart or TSC and buy a gallon jug of Slime and put it all into the tire. That way, you'll fix your small leak and any other small leak you might have later in the tire. As a matter of fact, if you have thorny soil, I'd slime all the tires. I'd put at least a full quart in each of the front tires and a gallon in each rear tire. Even if later you decide to fill the rears for ballast, you will probably not have any problems because the tiny holes will be permanently plugged with slime.
BTW: You can buy an expensive tire seal by the 5-gal bucket, but it is pretty darn expensive, around $175. This stuff has little rubber particles in it and will permanently seal a tire. It was made especially for tractor and construction equipment tires, but it is about twice as expensive as Slime.