The White House Garden: Not Organic?

The White House garden has been a big success so far, with more than 1,000 pounds of food grown last year. Those veggies and herbs have gone to charity, provided a nice educational example for kids, and occasionally contributed to state dinners. But is the garden organic? Apparently not:
Assistant White House Chef Sam Kass, an old friend of President Barack Obama's who oversees the garden, says labeling the crops "organic" is not the point, even though the White House uses only natural, not synthetic, fertilizers and pesticides.

"To come out and say (organic) is the one and only way, which is how this would be interpreted, doesn't make any sense," Kass said as he walked among the garden's newly planted broccoli, rhubarb, carrots and spinach. "This is not about getting into all that. This is about kids."

...Kass and aides to Mrs. Obama will not elaborate on why the garden is not technically organic.

Someone help me out. If they're not using synthetic fertilizers or pesticides, how could the garden not be organic? Are they using genetically modified veggies? Also: Does it matter if it's not organic?