Ensuring good soil health beneath our Saint Augustine lawns is the single greatest determining thing we can do to ensure a beautiful healthy and lush Saint Augustine lawn for the entirety of its lifespan. Sandy soils can present a problem for Saint Augustine grass which can be almost as bad as heavy clay soils, albeit due to very different circumstances.
Sandy soils are often highly alkaline in nature, which can be as bad for a lawn as highly acidic soils can be. Sandy soils by their nature usually lack a healthy soil nutrient profile and as a result will often be unhealthy much of the time. Unhealthy Saint Augustine lawns will be weak and can develop bare patches and invasions from weeds and diseases.
Another problem with some sandy soil types is that they can be highly water repellent, meaning the soil cannot circulate water effectively across the entire soil profile, and cannot hold onto water for long periods of time. And the problem here is that the lawn will require more watering more often than should otherwise be normal.
Over the life of the Saint Augustine lawn being grown on sandy soils, we can therefore expect the turf to be less than what it should be, never as green as it should be, never as lush as it should, and often having more problems than what would otherwise be expected.
With these things in mind we can see that improving sandy soils prior to laying new Saint Augustine turf can be a very worthwhile decision to make. So lets take a look at our options.
Minor Soil Improvements
Our first option to improve our soil for Saint Augustine grass is to add minor nutritional products to the soil and raking them through to gain a more organic base for the turf to live on.
Such products will usually be organic in nature, things like blood and bone, seaweed products, soil improvers based on animal manures etc. All these things are fine, and the only products we would really want to avoid would be fresh manure products, which could in fact cause major health problems for the new sod after its laid, due to the strength of the nutrients the new turf is being exposed to.
If using fresh manure products, then it would be best to leave the improved soil bare for some time prior to installing new sod, as this would greatly benefit the soil itself, as well as breaking down the strongest components of the manure into the soil, and prior to the laying of the sod. Preparing the soil at the onset of Winter, and then laying the new sod at the beginning of Spring would be a wonderful way to do this.
In most cases these products will be of temporary benefit in nature and will not provide a good long term solution to having a new St Augustine lawn being grown on poor sandy soils. With this in mind we should consider this course of action as being for sandy soils which still have some decent nutritional value to them.
For sandy soils which have very little nutritional value or organic matter present in them, then we would be looking for a far better and more long term option and solution to improving lawn soils, before laying our new St Augustine lawn.
Topsoil Replacement With Sandy Loam
A more long term solution for getting past the problems of growing Saint Augustine grass on sandy soils is to replace the layer of topsoil on which the Saint Augustine grass will be growing for its entire lifespan.
With this solution we really are providing a long term foundational basis for our new Saint Augustine lawn. Ensuring our new turf will survive, grow and flourish as best as it possibly can.
In doing this, we will be wanting to remove the top 8 to 12 inches of soil, and disposing of it. In its place we will then lay new sandy loam from the soil supply shop.
This is a far more expensive option, and more so as the lawn area gets bigger and we will need to hire a digging machine operator to dig the topsoil out and dispose of it afterwards: hopefully by improving and reusing it elsewhere in the garden. Then of course having the new soil delivered and installed.
These really are our only two options available to improve a sandy soil for laying a new Saint Augustine lawn onto. Either soil improvement or soil replacement. If we choose to use sandy loam or another similar lawn soil type or soil mixture to replace the sandy soil is not what’s most important. Improving the soil prior to laying the new Saint Augustine turf is what is important for the future health of the lawn for decades to come.
Of course, whatever our concerns as to the best solution to our lawn soil problems then we all must work within those limits and adjust our practices accordingly. So if topsoil replacement is not viable or is otherwise unwanted, then some other type of soil improvement would be far better than doing nothing at all.
Last of all is if we have St Augustine grass lawns which are growing on sandy soils, or any other type of soil of poor quality, then we will need to ensure we always pay careful attention to the nutritional requirements for the turf. And we do this by implementing a good year round lawn fertilization program with the use of good quality lawn fertilizers, which include trace elements, and phosphate.
Choose the best solution for your own home by carefully assessing all factors involved in either decision, prepare the soil well in advance of laying the new turf: the longer the better, as this allows nutrients and organic matter to fully break down into the soil, and for the soil to settle prior to laying the new sod.