Why is my lawn yellow
A yellow lawn can be caused by numerous things however the most likely causes are drought, lack of nitrogen and compaction in summer however the lack of sun is the most likely cause in winter as the chlorophyll (green colour in plants) does not get replaced fast enough. There can be other causes including chemical burn and soil compaction can also be a strong cause.
If your lawn is more brown then yellow, that could be a bad sign. Outside of winter dormancy, brown grass typically means dead grass. We can easily run some simple at home tests to see what could be causing your sad lawn and how to fix it.
How do we know the cause?
I have created a simple list to help you identify the likely causes visually. If the visual identification below seems too vague or need to be confirmed, make sure to read further down as we go into more testing methods.
First of all, water! Are you watering? if not, water your lawn. I always recommend a good solid water once a week rather than a trickle a day. This lets it get right into the soil.
Secondly, is it winter? Less sun, less chlorophyll and less green the plant will be. Sometimes patiently waiting for spring is all we can do.
| What you see | Most likely cause |
| Whole lawn, uniform pale yellow | Nitrogen deficiency |
| Whole lawn, straw-coloured, cold weather | Winter dormancy |
| Random irregular patches, appeared fast | Lawn grubs / army worm |
| Circular patches | Fungal disease |
| Yellow centre with dark green ring | Dog urine |
| Straight stripes or bands | Fertiliser burn or mower error |
| Frayed whitish tips, whole lawn | Blunt mower blades |
How to test for why your lawn is yellow?
Sometimes visually isnt enough and you need a more mechanical or physical test. There are 3 different tests that we recommend to further identify the common causes of yellowing which include:
- Tug test
- Screwdriver test
- Cloth test
Lets go into each of these and how we can use them to further identify some likely causes.
Tug test: Is the lawn dead?
Go to a patch of lawn that is yellow/brown and pull a bit of grass out. If it comes out easily with little force, its most likely dead. This is an easy test to do during winter. If there are patches that are yellow and still strong, wait till spring and add some general lawn fertiliser to help it boost back. It may only take a month before it fully recovers.
Screwdriver test: Is the soil compact?
Using a screwdriver push it into the soil that the yellow lawn is on. If the screwdriver does not easily go into the soil, it means the grass is too compact and the roots are struggling to grow and get water. You need to use a coring device to add pockets into the lawn for water to get into, adding a sandy top soil will be needed to level the lawn and fill in these holes. The recovery might not happen immediately and may require months or years to fully grow back (depending on how compact and how dead the lawn is).
Cloth test: Do I have lawn grubs?
Get a wet/damp cloth or towel and lay it flat on a parcel of the yellow lawn. Wait for approximately 10 min before removing the cloth. If you see lots of grubs surface after the cloth is removed you may have a problem. We recommend purchasing a product like acelepryn and following the instructions on the packet to treat your lawn. Depending on the damage lawns may take a month or two to recover.
3 tips to preventing a yellow lawn
Preventing a yellowing lawn can be easy 9 months of the year (except winter, grass goes through pretty hard times). How can we actually prevent this from happening?
- We always recommend watering regularly. A good solid water once a week, soaking into the soil can do wonders for the lawn health.
- Don’t over fertilise and test before applying any chemical. Applying too much fertiliser can overpower the plant and root system. Dont do it. Follow the instructions on the packet for the optimal performance. Also make sure before applying any chemical (weed sprays, pesticides and fertilisers) to test in a small area first. Sometimes hiring a professional with experience can help.
- Treat lawns for grubs twice a year. Using a product such as acelepryn will not only kill the grubs but will also prevent them for up to 6 months. We recommend applying this so that you never have to worry about grubs in your lawn. You can also use fungicides that will help prevent fungal diseases (which can often be hidden till the lawn goes brown and are much harder to diagnose).
Hopefully now you are a little more knowledgeable in identifying why your lawn could be yellow.