Tripod Short Center Columns
Most tripods enable you to gain additional height by extending the center column. I've written previously though that doing so will reduce the stability of your tripod, effectively turning it into a monopod with three legs. But you're still carrying around the darned thing even if you're not using it, and it's still getting in your way when you want to lower the tripod close to ground level. So what are you supposed to do?
Depending on the model of tripod you have, there may be an answer in the form of a short replacement center column. These handy objects are exactly the same as their original, longer counterparts, except they are, well, shorter. Both Gitzo and Bogen/Manfrotto make shorter center columns for at least some of their tripods.
Replacing your center column with one of these will give you the freedom to go much lower, and will also lighten your load at least marginally. Unless your tripod isn't tall enough and you're forced to use the existing center column, do yourself a favor and get a short column if one is available for your tripod. You'll be glad you did.