grass dew

Have you ever gone for an early morning stroll when the sun is shining, walked across a lawn, field or patch of turf and realised that the grass is wet?

Well, that's known as 'morning dew' and appears on grass early in the mornings or late at night when the right weather conditions are present.

In this blog, we take a closer look at dew and answer the age-old question 'why is grass wet in the morning'. 

So, without further adew (pun intended), let's get into it...


Where Does Dew Come From?

Moisture is constantly circulating in the air, often referred to as humidity. When you see dew present on grass, spider webs and leaves, this occurs as a result of the water vapour condensing out of the air caused by a fluctuation 'dew point' and air temperature. 

Dew occurs when certain objects cool and drop in temperature. A perfect example of this when you have an ice-cold glass of soft drink and water appears on the bottom of the outside of the glass. This is exactly what happens with dew. As a result of a sudden drop in temperature to the dew point temperature, water particles that float around in the air suddenly condense to form the water drops that you see on grass in the mornings.


What is dew point?

Dew point is a specific daily temperature at which water must condense out of the air from its vapour state. Once this temperature is met, the air cannot hold any more moisture and therefore releases it. 

An important thing to note regarding dew point is that it can never be higher than the surrounding air temperature. For example, you cannot have a 20-degree celsius air temperature with a dew point of 30-degrees celsius. Wet grass in the morning indicates that the water vapour in the air had to condense overnight because the dew point was reached. 

If the temperature gets low enough during the evening, dew may be subject to another transformation. Here, dew freezes to a solid form which we commonly refer to as 'frost'. So, when you wake up during the winter or early spring and see frost covering your lawn, just know that dew has formed and the cold temperatures has transformed it into frost. 


Is it ok to mow grass with dew on it?

Now, if you've planned to care for your lawn and decided that you need to mow it but have woken up to find that it's covered in dew, you're probably asking yourself whether it's still okay to do so, right?

Well, we're here to tell you that this is something that you might want to avoid as best as possible. We understand that sometimes you may be limited with time and that the only time you can mow it is in the morning when it is wet but trust us, don't. 

Wet grass simply doesn't cut as well as dry grass does, meaning you are far more likely to cause damage. Damage that can take a long time and effort to repair. Not only that, but you can also cause damage to your lawnmower with grass clippings sticking to the machine.

Again, we know that it is sometimes an unavoidable task but if you can avoid mowing your grass with dew on it, you will find your lawn to be much healthier as well as easier to cut.

You can find more lawn care and advice on mowing by clicking on the button below.

Lawn Mowing Tips >


For more information on why grass is wet in the morning or on whether you can mow grass with dew on it, be sure to get in touch with a member of the Lawn & Weed Expert team - we'd be more than happy to help!

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