Yellow sod is something no one with new sod wants to see. It can be even more alarming if your lawn seems to turn yellow overnight 6 weeks after being installed. I’ve been through several scenarios where my sod has turned yellow or brown in patches and have managed to successfully repair it.
Keep in mind that these patches, as unnerving as their appearance may be, are often a warning sign that something is wrong and that it can be corrected. Identifying those problems is your first step to finding a solution.
Why is My Sod Turning Yellow? – The Short Answer
Sod typically turns yellow when it has too much water or not enough nutrients. There are many other possible reasons, explained below, but these two are the most frequent. In both cases, it is possible to get your lawn back to its original, lustrous green fairly quickly.
Reasons Why Your Sod Might Be Turning Yellow
Having to ask, “Why is my newly laid turf turning yellow?” is something anyone investing in sod dreads. There are many reasons why your sod could turn yellow, below are the most common reasons and several less common, as well as how these conditions may be identified.
1) Too Much Water
This is, by far, the easiest trap to fall into with new sod. You may be tempted to water it the same way you had watered your old lawn from day one. Or perhaps you soak it every day to give it a little “boost”. When I first worked with sod, I ended up overwatering it. It started to turn yellow around the edges. The good news is that I had well-draining soil at the time and a few days later, following the right protocols, my lawn recovered.
Too much water around the new sod will discourage it from setting roots into the soil. This can also lead to root rot and mold infestation if left untreated. Too much water is the primary cause of yellow sod.
2) Not Enough Nitrogen
A lawn turning yellow, not brown, is a big flag for lack of nitrogen or another primary nutrient. While too much fertilizer in the early stages can “burn” your lawn and turn it brown, a lack of nitrogen can leave your lawn with a “washed-out” look.
This is especially true if you’re on your 3rd week or later after placing the sod, as many of the other possible reasons for your lawn turning yellow would have already manifested by the second week. This is one of the reasons your lawn might start turning yellow after it has started to root even when by all other measures it seems to be perfectly healthy.
3) Mold or Mildew Infestation
Mold and mildew can do a variety of things to your sod that will cause it to turn yellow. It can start to break down the blades of grass or roots. This may initially cause a sudden burst of a bright green, healthy color followed by a sudden turn to yellow. If you do have a mold or mildew infestation, you may notice that your sod seems slimy or dusty, depending on the variety you’re dealing with. If the mold remains long enough, you may notice an unpleasant, rotten smell near the yellow patches of your lawn.
4) Impenetrable Soil
Soil can become compacted during or before the sod installation process. This is one of the reasons good soil prep is essential to a healthy lawn created from sod. Soil that is too hard prevents roots and even stolons or rhizomes from getting a good hold and this, in turn, keeps them from getting the water and nutrients they need from the soil.
Alternatively, the soil can be so compacted that not even water will filter through. This is also known as hydrophobic soil. Hydrophobic soil will not only fail to absorb water but actively repel it. This can result in water pooling under the roots of your new sod.
5) Failure to Root
Failure to root will cause a lack of water and nutrients for your new sod unless it is being given regular water and foliar feed. However, giving near-constant light watering and frequent foliar feed will prevent your grass from rooting, even if it doesn’t turn yellow. Following best watering practices can encourage your sod to take root without turning yellow.
6) Inconsistent or Incompatible Cold
While it is possible to place sod in the winter when temperatures are approaching freezing, this should only be done if there is little to no chance of the weather warming back up. If things stay cold enough, the sod should enter and remain in a dormant state until the spring when it will green back up fully.
If the temperatures are inconsistent, say dipping to -2F and then warming up to 40F for a few days later in the week for several weeks in a row, you may begin to see that your sod is developing yellow, sludgy patches. This may mean that the plants are freezing and thawing frequently enough to damage their cells.
7) Mild Chemical Exposure
If you used the chemical burn method to get rid of your old lawn and didn’t wait long enough or failed to prepare the soil before placing your sod, residual chemicals could still be in the top layer of the soil. This can cause discoloration of the sod. If the sod only turns yellow and not brown, it will likely recover from this exposure with little to no intervention, as long as it’s still growing.
8) Common Dieback
Nearly all sod, especially of the stolon or rhizome-producing varieties, will experience a little dieback along some of its edges. This is most common for sod placed during the heat of summer or sod that is at the edges of a watering zone before it develops proper roots.
Will Yellow Sod Turn Green Again?
Yes, yellow sod will turn green again as long as the primary problems are addressed. All of the reasons sod might turn yellow listed above have solutions that will help you get your lawn back on track. Yes, it will take a little longer to have the lush, green lawn of your dreams but it’s still possible. Sod isn’t less or more difficult than seeding a lawn.
To get your lawn on track, you need to identify why your lawn is turning yellow and then correct that problem. If it lacks nutrients and hasn’t rooted, for example, you should apply a light feeding of liquid or foliar fertilizer. If it has begun to root, a light application of granular fertilizer would be appropriate. If there is too much water, encourage draining and allow the lawn to dry out for a day or two until there is no standing water.
Each problem has specific steps to get things back to where they should be. For a more thorough explanation of how to save dying sod, and more examples for each of the causes we have mentioned above, you can read these tips on how to save dying sod.
When Sod Turning Yellow Shouldn’t Make You Worry
After all of that information about the reasons why your sod may turn yellow and the problems it could potentially indicate, there is a single natural reason for a little bit of your sod to turn yellow that is worth mentioning. If you’re following a schedule to get your lawn from the daily, light watering it needs initially to the deep watering that will encourage it to root, you could start to see some intermittent yellowing of individual blades or your lawn may look “speckled”.
The first few times you see this it can feel like something is wrong. However, I have seen many lawns go through this process. What’s happening is that, as the sod begins to root and the sections begin to mesh, some of the grass may “shed” or be compartmentalized, die off, and then be replaced by healthier, new grass. This stage will likely last about 10 days and begin somewhere around the 5th or 6th week after placing your new sod. This speckling is not cause for concern. However, if patches larger than 2” in diameter do begin to develop, something else is going on.
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