Saint Augustine grass is a lawn type which is ideally suited for partial shaded conditions. Not only does Saint Augustine have very good shade tolerance amongst all the warm season lawn types, but it can sometimes perform worse when grown in full sun. The most noticeable detrimental effect of Saint Augustine being grown in full sun is that its thatch layer grows at greater speed and to a greater depth when grown in these full sunlight conditions. For these reasons, we can see that Saint Augustine grass is a lawn type that performs at its best in partial shade conditions, over full sun conditions in all warmer regions.
Lawn care practices for any lawn being grown in partial shade will differ than when a lawn is grown in full sun, and our Saint Augustine lawn is no exception.
The most common lawn care practices which will need to be altered for Saint Augustine grass being grown in shade will be to monitor for possible problems such as moss and bare patches, reducing watering times to grass grown in shaded areas, and lawn aeration if the soil is becoming water logged. Which are all issues that may most often occur when too much shade is present on any lawn.
However, the number one factor which needs addressing for St Augustine lawn grown in partial shade, and which can dramatically alter so many other aspects of our lawn health in partial shade, is when it comes to adjusting our lawn mowing heights correctly for these conditions.
Lawn Mowing Heights In Partial Shade
We all have an understanding of photosynthesis in plants, including turf. It’s a process of food production for plants and is vital for plant health. Which is why many plants and lawns simply cannot grow in shade, they need at least some direct sunlight to survive.
When we remove or reduce this direct sunlight (due to shade levels), photosynthesis decreases, and plants and lawns can go into poor health, suffer problems, or even die off as a direct result of lack of photosynthesis which is powered by sunlight. Which is why all lawns will die in heavily shaded areas.
When we look at photosynthesis in turf, we can now understand that in reduced light conditions, the longer the length of the leaf of the lawn equates to a substantial increase in overall leaf matter of the lawn, and as a result this will also increase the photosynthesis levels of the lawn itself.
So by doubling or even further increasing the lawn mowing height for lawns growing in partial shade, we are actually doubling the photosynthesis levels of that lawn being grown in that area, and this results in an incredible increase in Saint Augustine lawn health in partial shade conditions.
Mowing Saint Augustine Grass in Shade
We've seen how lack of direct sunlight from growing lawns in partial shade results in reduced photosynthesis, which then results in poor lawn health or worse for lawns grown in partially shaded conditions.
Now Saint Augustine grass is indeed the best warm season lawn type to grow in partial shaded conditions, but just be aware that even the Saint Augustine lawn will require some direct sunlight each day in order to survive, there's no such thing as a grass which will grow in full shade.
Now it’s time to translate everything just covered into a single and simple lawn mowing fact for Saint Augustine grass.
We must increase lawn mowing heights for Saint Augustine grass being grown in partial shade in order to ensure the greatest possible health for our lawn under these conditions.
Raise Saint Augustine lawn mowing heights higher as shade levels increase. The more shade, the longer the leaf of the Saint Augustine lawn should be.
2 to 4 inch lawn mowing heights should be minimum for Saint Augustine grass in shade, however as the shade levels increase, so too should our lawn mowing heights, we can easily go way up to 5 inch lawn mowing heights for Saint Augustine grass in heavier shaded conditions.
Just remember though, even Saint Augustine grass has upper limits to its shade tolerance, and once shade conditions reach past the 70% mark, the chances of maintaining a healthy Saint Augustine lawn in shade will become almost impossible.