I've watched for months as my mother-in-law has harvested grass from one lawn and planted them in hers. It has been interesting to see how the grass reacts to being transplanted. In the process she has also bought some sod squares to place in her new lawn. Some of the grass she transplanted and some of the sod turned yellow.
What makes new grass turn yellow? Well, it turns out that there are several factors that can affect new grass turning yellow. The main causes are:
- Too much or too little nitrogen
- Lack of iron
- Too much or too little water
- Lack of sunlight
- Cold temperature stops photosynthesis
- Frost can damage grass
Too much or too little nitrogen
Grass needs nitrogen to grow. It is an essential element needed in photosynthesis. Your new grass can't produce chlorophyll without nitrogen.
When your new grass has too little nitrogen, the photosynthesis process is hindered. This causes the grass to produce small amounts of chlorophyll. Chlorophyll is what makes grass green. Without it, or when it is in limited supply, your grass will turn yellow.
If you have too much nitrogen, you run into a different problem. Too much nitrogen makes your soil acidic. Acidic soil makes it hard for your grass to absorb water. This will in turn cause your grass to turn yellow.
To find out if nitrogen is the problem with your new soil. Get a soil test kit and determine how much nitrogen is in your soil. If the nitrogen is too low, then add a fertilizer that is rich in nitrogen to your new grass.
If the nitrogen is too high for you new grass, you should water your lawn with extra water. Try to keep the soil wet so the water can help the soil clear out some of the nitrogen. Do this regularly for a few weeks and you should see green grass start to appear. Periodically test the soil during this process to see what the nitrogen levels are under your grass. Once the nitrogen levels reach a safe level for your new grass, stop applying extra water.
If there is any dead grass left after the green grass appears, remove it. Then plant some new grass.
Lack of Iron
Iron deficiency, also known as iron chlorosis, can cause your grass to turn yellow. Just like nitrogen, your new grass needs iron for photosynthesis.
It is usually not practical to test the iron levels in your soil. You can order a complete soil analysis; iron testing will be part of the complete test. You probably won't need a complete test.
If you added compost, manure, or other nutrient rich fertilizers to your soil, then iron should be in your soil. First, check to the pH of your soil to see if it is above 7. If the pH is above 7, your grass may not be able to absorb the iron already present in the soil. If the pH is high, add nutrients, like sulfur or coffee grounds, to your new grass' soil to lower the pH.
Too much or too little water
Water is also vital during photosynthesis. If you have too little water, your new grass will not have enough water to absorb and combine with carbon dioxide to produce glucose and oxygen molecules during the photosynthesis process.
If you have too much water, your new grass will basically shutoff absorbing water because it is overwhelmed. This will also cause it to not absorb other vital nutrients to complete the production of chlorophyll correctly.
As mentioned above, in the scenario where you have too much nitrogen, you may have to over saturate your new lawn with water to dilute and wash away excess nitrogen until the nitrogen is at a safe level.
Lack of sunlight
Your new grass needs sunlight to create chlorophyll. If yellowing of your new grass is happening in spots where there is not much sunlight throughout the day, you need to try and move what is blocking the sun. Trim hedges and trees to allow sunlight to hit your new grass.
If you can't get direct sunlight on your grass, you can try using a reflective material to bounce the light off of and onto your grass.
In low light areas, be careful not to over water. Because your new grass is not in the sunlight, water will evaporate at a lot slower rate.
New fescue grass turning yellow
fescues grass likes mild temperatures somewhere between 60-80 degrees F. Temperatures below this will cause the grass to stop growing. Photosynthesis will stop during this period. This will cause yellowing in your fescues lawn.
New grass turning yellow after fertilizing
It's frustrating. You've just fertilized your new lawn and expect to see some good results. When you go outside to check it, you are mortified to learn that it has turned yellow. What made your grass turn yellow after you fertilized it.
When the right amount of fertilizer is applied to a lawn, you will see the lawn grow healthy and strong. When too much fertilizer is place on a lawn, it burns it. It is this burning that causes it to turn yellow.
What is actually happens when fertilizer burns grass? When too much fertilizer is applied your grass gets overloaded with nutrients. Particularly, there is too much salt in the soil. This abundance of salt causes the grass to not be able to absorb enough water and the proper amount of nutrients it needs for photosynthesis.
How to fix fertilizer burn
The easiest way to fix fertilizer burn is to reduce the amount of fertilizer in the soil. If you just place the fertilizer on the soil, you can try to clean up as much as possible. If the fertilizer has already gone into the soil or is unretrievable, you can dilute it by watering your lawn. You can also try cutting your grass and bagging the clippings. This will help to remove some of the damaged grass.
Why is my new sod grass turning yellow?
New sod is grass that was grown somewhere, cut, and then planted in another location. In this case, that place is your lawn. When you planted the grass, it looked beautiful and green. Now it is starting to turn yellow. Your new sod is probably turning yellow because it is drying out or it is over watered. Place your sod on a regular schedule for watering at least once a day. You can also water it twice a day, but don't over do it.
Will yellow grass come back?
Yellow grass will usually come back as long as it is not dead. If your grass is yellow because it is dormant, you may not need to do anything to help it grow again. Once it finishes its dormant cycle, it will start growing again.
If your new grass has turn yellow because of lack of sunlight, you can help it by giving it more time in the sun. Remove whatever is preventing it from having the sun's rays land on it. I have a van that I sometimes park on our lawn for extended periods of time. The grass always turns yellow when I leave it there for a month or longer. When I move the van and let it get ample amounts of sunlight, the grass always bounces back; turning green again.
New grass turning yellow in winter
Cold temperatures will turn new grass yellow in the winter. Cold temperatures slow or stop the photosynthesis process in grass during winter. Once the temperatures rise again in the Spring, your grass will start to turn green again.
Sometimes frost is the culprit in winter. If frost has turned your new grass yellow or brown, it may be a sign of it dying. The extend of the damage really depends on how deep the freeze has been on your new grass.
Some experts recommend watering your new grass before a freeze to give the new grass ample water to absorb and to insulate against the freeze. Also, they suggest letting your new grass grow a few inches before winter. This will help protect the vitality of the new grass.
If you are planting new grass, you should plant it well before the winter or fall. The most ideal time to plant new grass is in the spring. Newly planted grass planted in the fall or winter won't have enough time to take root before the first frost.
New bermuda grass turning yellow
Your new Bermuda grass likes warm temperatures. The best temperatures for Bermuda grass are above 65 degrees F. Bermuda grass thrives in warmer environments with temperatures between 95-100 degrees F. If the temperature drops below 60 degrees F, Bermuda grass will slow photosynthesis and yellowing will occur.
Also, underwatering or overwatering new Bermuda grass can impede it's growth.