The Pavement Effect
Blowing leaves through 6″ Bermuda or Zoysiagrass is painstakingly slow. At that height, the turf has formed somewhat of an inverted canopy that essentially just traps leaves within the tillers; and once the turf has gone dormant, it becomes more like a well-worn straw broom. You know those dust bunnies you sweep from your floor, but you can never seem to shake from the end of your broom? It’s the same principle. By bringing the turf down to a shorter height—slowly, while transitioning into Autumn—it greatly enhances my ability to work more efficiently, and to keep the lawn looking cleaner. This is especially true while blowing wet leaves. A higher cut would make in near impossible to keep the lawn managed with a flat, compact appearance, because I would first have to blow them out of the turf, and then across the turf. Blowing leaves—wet or dry—across a shorter, more compact turf is a lot like blowing them across pavement.

Let The Sun In
Contrary to what you may have heard: Southern Turfgrasses rarely enter into complete dormancy—it simply doesn’t get cold enough or stay cold enough for the length of time required to achieve complete dormancy. We do generally have a good bit of precipitation though; which, on a lawn with a long Winter coat, can mean flattened turfgrass, pooling water and a rotting root system. Having the turf closely cropped, allows the turf to maintain it’s upright stature, while easily allowing the sunlight to more easily dry saturated turf. A tall Winter coat, over saturated turf, during a warm spell of low 60’s in the middle of January is laying the groundwork for major disease problems in the Spring. I’m a pro-active kind of guy.

Springing Into Spring
Spring green-up has everything to do with soil temperature. Once soil temperatures reach roughly 60° or so, the turf will begun to send new tillers up. The more quickly your turf can take advantage of those warm March afternoons, the quicker you will begin to see your lawn greening. With a thick, dank Winter coat laying across your lawn, it is near impossible for the warmth of the sun to reach the soil.
Towards the end of April, I will begin scalping lawns. Having already brought them down quite a bit going into Winter, scalping generally only takes a couple of visits, dropping an inch or so in height on each visit. Even before scalping, most of my lawns are already showing considerable degree of greening. Once the scalping is complete, green-up usually occurs rather quickly.

That about sums everything up… there are a couple more reasons why I feel a lower turf height is needed during the cold months, but they are purely aesthetic and have no bearing on the health of your lawn. As always, if you have a question about anything, leave a comment; I’ll answer you to the best of my ability.