Sandburs grow best in sandy soil tht are low in organic matter, ie. poor soils that will not support a good, healthy stand of grass or other plants. There are pre emergents that can be used for short term control but for long term control the soil problem needs to be addressed.

Here is a link that might be useful: Controlling Sandburs

Kimmsr, you are speaking out of ignorance of the subject matter, I am afraid.
Sandburs grow like crazy in sandy soils...but sandy soils are not an easy fix! One can add organic matter in large amounts on a regular basis, but it (the OM) will quite rapidly disappear into the vast, sandy pit. Been there, done that.

Also, Centipede is a grass species that does very, very well in sandy soils and is a common choice for those areas.

Don, your best bet is to contact your local extension office
and obtain a good program for the maintenance of a healthy stand of Centipede. So many people think that this is a turf that thrives on neglect, but that simply isn't true. It will struggle on where other warm season grasses won't, but it will never thrive.

Centipede thrives on regular fertilization, mowing, and watering practices. By encouraging a thick stand of grass, you will automatically discourage sandspur and other weeds.

Other essential information to obtain from your extension office will be a regional calender for pre-emergent applications. Timing is essential. It will be dependent upon your local climate and weather conditions.

Rhizo, I have sandburs here and I have controlled them simply by adding lots of organic matter to that soil and then getting a good, healthy turf established. If you did not control them you simply did not add enough organic matter to the soil.

Pick the sand spurs, burn off the spines, and eat them

Thanks for the info guys.