Water is the simplest choice for controlling arena dust. It’s time consuming and you do need a good source of water, but otherwise it’s tough to beat. Water will work, if you apply it right:
1) Water deeply. Get 2 to 3 inches below the surface. It’s more effective to water deeply and less often then to water frequently but just on top.
2) Water in the evening. It can settle below the surface overnight and thus not evaporate as quickly. If you also need to water during the day, you won’t need to run the water as long because the sub-surface will still be damp.
3) Hand-rake the ruts. That way they won’t compact and the water will penetrate and not pool.
4) Water uniformly. Spots that stay wet can become slick. They can also affect the stability of the base, making it uneven.
5) Get a rain gauge or moisture-meter from a garden shop. When you learn how much you need to water to get the sub-surface sufficiently wet, note the level on your meter. You then just need to check the meter when watering to know how much is enough.
If you want a commercial dust control product, see October 2008 (www.horse-journal.com).