At what age should a horse first be ridden?

How young is "too young to ride" is often a heated debate among horse people. My opinion is just one of many but I hope that you'll take the time to research some things (don't just take my word for it) before you form your own opinion of when you should begin riding a horse.

Many people are under the impression that it's okay to begin riding a horse at 2 years old. When I'm talking to people with this belief, the next sentence that follows (without fail) is: "they run racehorses at 2 years old". And I might as well go ahead and say it: This must be one of my #1 pet peeves when it comes to horses.

What many people don't realize is that yes, racehorses are ridden at 2 (often at 1 yr old) BUT racehorses are usually retired by 6 or 7 years of age. Many are retired before that. The most sickening part is that many are permanently lamed and many have to be euthanized (put to sleep) by the age of 2, 3 or 4. I wonder how many yearlings are injured while in training and euthanized before they ever make it to the racetrack that we will never hear of?

If a horse survives the training for racing, and lives long enough to be retired, almost every one has arthritis and joint problems from being ridden so hard at such a young age and are no longer rideable after racing. To me, it's a sad, sad thing to see a horses life ruined at such a young age as 6 or 7, just to "entertain" and make money for people.

Before you begin riding a horse, please consider that a horses skeletal system is not matured until they are around 4 years old, (some breeds take even longer to mature). Their bones are simply not fully formed, not strong enough and not designed to carry a persons weight at 2 years old. Riding a horse too early causes all kinds of joint problems.   Update 8/31/2016:  Please read this article:   TIMING AND RATE OF SKELETAL MATURATION IN HORSES, With Comments on Starting Young Horses and the State of the Industry

If you want to do what's best for your horse and help to lengthen their lives, it's best to begin "light riding" (such as in the ring or on easy trail rides) when the horse is around 3 years old, and no "hard" riding (such as galloping with a rider) until 4 years old or more. I know some people who do absolutely no hard riding until the horse is 5 or 6 years old.

There is lots of ground training that needs to be done and many ways you can spend time with and enjoy your young horse while waiting on them to get old enough to ride. And it's worth the wait. Think of the long run: If you are patient and allow your horses' bones the time to grow and mature, you can have a strong, healthy riding partner that can happily carry you well up into their twenties. 

UPDATED NOTE 8/31/2016:   

I know this is a subject that generates a lot of passion from horse owners and trainers.  
I BESEECH YOU to read this informative article by Deb Bennett, Ph. D.

TIMING AND RATE OF SKELETAL MATURATION IN HORSES, With Comments on Starting Young Horses and the State of the Industry