A law that requires the Legislature to establish a state limit on public school spending 18 months in advance should be repealed, Gov. Terry Branstad said Monday.

The budget limit, commonly known as allowable growth, has been a longtime law that school advocates say helps schools plan future budgets before they lock in tax rates, certify budgets with the state and enter into contracts with staff.

It's also an indication of how much the state will give public schools on a per-pupil basis.

The rate in the current fiscal year is 0 percent, the lowest in the nearly 40-year history of the school budget formula. The 2012-13 school year will see a growth of 2 percent.

Branstad said Monday that his administration doesn’t want to set the outlying year’s growth rates so that it can instead focus on a number of education reforms that are bound to cost the state more money, like teacher compensation and potentially tinkering with the length of the school year.

He further said that the provision requiring the Legislature to set the growth rates within 30 days of starting its annual legislative session should be repealed.