(CNN) -- Leanne McCain said she didn't know about Wreaths Across America until her husband, Bryant, was killed in Afghanistan in November 2011.
Now she's a big supporter of the program, which places holiday wreaths on his gravestone and the resting places of other war dead at Arlington National Cemetery.
"There are so many people who don't have any family or friends, especially the older veterans," said McCain, of San Antonio, Texas. "For them to get a wreath at Christmas is incredible."
Thanks to a surge in donations, wreaths will cover more than half the gravestones at Arlington this year.
Two weeks ago the group Wreaths Across America only had enough money for 95,000 wreaths at Arlington, far short of its goal of 135,000, said Amber Caron, Wreaths Across America spokeswoman.
But news stories about the wreath shortage caused a flood of late donations.
"We ended up with more than our goal at Arlington, placing a little more than 143,000 wreaths there today," Caron said Saturday. About 25,000 people braved the cold to participate, she said.
Donations came from all over. High school students attending School of the Ozarks in Point Lookout, Missouri, kicked in $5,000. School spokeswoman Emily Hughes said students were saddened by the wreath shortage because alumnus General Tommy Bell is buried in Arlington.
"The students have a club called Pitch in for Patriots and even though they were out of school due to snow, they used social media to message each other and voted to donate $5,000 of their club money," Hughes said.
Caron said Arlington has about 240,000 grave markers. Volunteers always make sure to cover Section 60, the area of the cemetery with soldiers from the wars in Iraq and Afghanistan.
Each wreath costs about $15 to make. The Worcester Wreath Co. in Maine makes the wreaths and trucks them to Arlington where they're fixed to the graves.
The tradition started in 1992, when the company donated 5,000 wreaths. Caron said many people don't realize the program is funded by donations, not the government.
McCain said she found out about Wreaths Across America through Facebook. "For this organization to do this is incredible," she said.
Last year, more than 400,000 wreaths were donated -- 100,000 to Arlington alone -- and placed at cemeteries in all 50 states. This year about 540,000 wreaths were placed nationwide, Caron said.
Caron said the ultimate goal is to cover every gravestone in Arlington, which is marking its 150th anniversary next year. Any donations made to the group's website will go toward the 2014 effort, she said.
People, groups or businesses can donate or sign up to volunteer at the organization's website.