While I have written about topdressing the greens in the past, I thought I would re-iterate why we topdress greens, but also talk about how we work the sand in to the green. For me, I have two goals in mind when I topdress. The first is to make the greens smoother. We have an incredible amount of foot traffic on our greens and by no coincidence, a lot of ball marks. Both foot traffic and ball marks leave indentations in the surface and the sand helps smooth them out. The second reason is to dilute our thatch layer to keep the greens firm and draining. Thatch is the layer of dead and decaying organic matter below the surface. Too much thatch and the greens get soft. If you get the thatch level right, the greens will be much firmer. A great example of this is any portion of a green that has bunker sand splashed on it all the time. I was walking across 5 canyon green the other day in the front and I thought I was walking on the cart path.
So knowing the benefits of topdressing you are probably asking yourself how the sand gets in the thatch. I have tried probably 10 different methods of working the sand in and this year I may have come across the best way. We allow the sand to dry as much as possible before play gets there and we then pass a brush over the green (picture right). 
The brush has an electric motor that allows the operator to raise and lower the brushes on demand. Immediately following the brush we
The brush has an electric motor that allows the operator to raise and lower the brushes on demand. Immediately following the brush we 
pass our vibrating rollers over the green. This further pushes the sand down to the base of the plant. Come nightime, we will turn the green sprinklers on for approximately 40 minutes to further push the sand down.
The end result is hardly noticeable to most golfers and provides a great putting surface to play on.
