Washington — President Bush plans to tell Congress tonight during his State of the Union speech to halve the number of earmarked spending projects, or else he will use his executive power to block them — but not until the closing months of his presidency. Mr. Bush’s challenge applies only to the 2009 fiscal year, not the spending package that lawmakers approved last month for 2008.

Earmarks are the controversial, noncompetitive set-asides — also called pork-barrel spending — that members of Congress sprinkle into annual spending bills to favored constituents. Colleges and universities have feasted on a growing supply of pork in recent years. Critics call the spending wasteful.

Mr. Bush plans to veto any spending bill for the 2009 fiscal year, which begins in October, that does not cut the number of earmarks in half compared with the 2008 version, a White House spokeswoman said today. In addition, he will order federal agencies on Tuesday to start ignoring any earmark listed in the Congressional reports that explain lawmakers’ intent but not in the text of the spending bills themselves. Most earmarks are placed in the explanatory reports and so are not legally binding.

However, any vetoes might be delayed for months: Congress typically does not complete spending bills for a fiscal year until well after it has started. Congress, which is controlled by Democrats, could delay spending bills for 2009 until after Mr. Bush leaves office.

In his State of the Union address one year ago, Mr. Bush also asked legislators to halve earmarks by the end of the 2009 calendar year. But he threatened no sanction if they failed. A Washington watchdog group estimates that total spending on earmarks of all kinds fell by half in 2008, to $14-billion, but that the number of earmarks increased by 10 percent.

Look for complete coverage of tonight’s speech on The Chronicle’s Web site Tuesday morning. —Jeffrey Brainard