June 8th, 2020 by Sarah Miles

Clearly, the main thing that we demand of our lawns is that the grass is lush and green. If your lawn is yellow, rather than the gorgeous green you’re looking for, it not only looks unsightly but is an indication of an issue you need to deal with.

There are a number of reasons why your grass has turned yellow. Here are the main ones and what you can do about it.

Heat and Drought

Prolonged periods of heat with no rainfall can cause your grass to go yellow or brown and it may look as if it has died, but this may not be the case. Grass has an inbuilt survival mechanism and will go dormant during periods of heat and drought. It basically shuts down to conserve moisture and nutrients and this is what makes it discolour. It can survive like this for around 4 weeks without water. You could just wait for rain or you could provide moisture by watering it and it should revive. A water butt is a great thing to have as it means you can still water your garden in the event of a hosepipe ban (plus it will save money for those on a water meter.

If it goes brown after just a couple of days of heat and no rain, it may be an indication that the grass is not rooted deeply enough. Try watering it very thoroughly but less frequently. This will encourage roots to grow down further to look for additional moisture in the soil.

Lack of Iron

Grass that doesn’t have sufficient nutrients, particularly iron or nitrogen, can become yellow. This is because all plants need iron to produce chlorophyll which is vital for providing them with oxygen. You can check this by doing a soil test to check the pH level. Adding iron into the soil is quite easy: you can treat it with iron sulphate. As well as restoring the grass to a vibrant green colour, this will also help it become stronger and more resistant to pests.

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Pests

Grass can help promote biodiversity and most insects won’t do it any harm. However, there are a few pests that can damage your lawn, such as chafer grubs and leatherjackets. They cause damage by eating the roots which weakens the grass. In addition, these plump grubs make a delicious meal for birds, who’ll happily dig up your lawn to get at them.

Luckily, iron sulphate can also help with this. Because it makes the grass stronger and healthier, it helps it to resist pests. It’ll also make your soil a little more acidic, which makes it less appealing for insects to lay their eggs in your lawn.

Over-mowing

While you may think that you’re actually helping the grass by keeping on top of the lawn mowing, you could be damaging it. By cutting it too short, it can prevent the grass from being able to absorb sufficient moisture. You’ll have a good idea that this is the cause because it will turn yellow shortly after cutting. Either wait longer between cuts or change the cutting height on the lawnmower.

Pet Urine

Just as grass needs iron to be healthy, too much iron can be harmful and this is why pet urine tends turn grass yellow. The best way to deal with this is to be on hand with a watering can after your pet has done their toileting so you can dilute the urine and minimise the impact.

If you do have yellow or brown grass, the good news is that most causes are treatable; it’s just a case of giving your lawn a little TLC!