Quoted:
I am specifically not looking for a 529 or some sort of account they can get a large chunk of cash at age 18.  I under stand they could liquidate a roth or ira but I think that is less likely.

The takeaway so far is that your child needs to earn income to make a contribution. However, it's important to emphasize that it doesn't necessarily need to be your child's money that is contributed -- in other words, as long as your child has enough earned income to justify it, there's no reason you can't make a Roth IRA contribution on your kid's behalf or match some of the money he or she contributes.
...
Here's an important point. One of the requirements, as mentioned, is earned income. But that does not mean your child necessarily needs to have formal employment. Self-employment income also qualifies, as long as it's reported to the IRS. (Note: If your child earns more than $400 from self-employment in 2018, he or she is legally required to file a tax return.)

For example, if your 14-year-old child earns $1,000 mowing lawns this summer, this income could be used as the basis for qualifying for IRA contributions. Other potential qualifying income sources are babysitting, or even chores you pay your kid for doing. (Note: I am not a tax professional. Be sure to consult one if you have any questions about what income qualifies for Roth contributions.)

One caveat is that by using self-employment income as a basis for qualification, your child may also have to pay self-employment tax on his or her reported income. Again, consult a tax professional to determine the potential tax implications of opening a Roth IRA for your child. Even if this is the case, the long-term benefits of Roth IRA investment at such a young age can more than offset this expense. And as I mentioned, if your kid earns more than $400 for the year, he or she should be reporting self-employment income anyway.

Anyone can have an IRA as long as they have income. My children are paid small (emphasis on small) monthly paychecks out of our family’s LLC. They will report this income in taxes at the end of the year. This is a win/win for us for a few reasons:

That $25/month we pay each of them is $25 less that we do not pay taxes on at our higher tax rate. Our family is taxed on that $25 at their toddler-size tax rate. Score!
Since their IRAs are Roths, they will pay the taxes on them in the years that they contribute and then NEVER again. They will not be taxed on their withdrawal of what they invested nor on the money they earn on their investments. (Learn the difference between a Roth and a Traditional here.)
Note: You don’t have to have an LLC to pay your children. You can pay them out of pocket and 1099 them at the end of the year the way you do your babysitter, contractor, etc. Although in this post I try to convince you that you should incorporate in your family.

Thanks to the Tax Cuts and Jobs Act (TCJA), your employee-child can use his or her standard deduction to shelter up to $12,000 of 2018 wages paid by your business from the federal income tax. For 2017, the standard deduction was only $6,350, but the TCJA nearly doubled it. So under the new law, your child can shelter almost twice as much wage income with the increased standard deduction. That makes hiring your kid a better idea than ever.

Bottom Line: For 2018, your child will owe nothing to the Feds on the first $12,000 of wages, unless the kid has income from other sources. Your kid can then set aside some or all of the wages and contribute money to a Roth IRA (more on that later) or a college fund.
...
When you hire your child, you get a business tax deduction (for employee wage expense) for money you might have just shoveled out to the kid anyway. The deduction reduces your federal income tax bill, your self-employment tax bill (if applicable), and your state income tax bill (if applicable).