It’s a common scenario. The weekend has arrived, the sun is shining, the kids are outside playing, and either mum or dad has fired up the lawnmower. After an hour or so of lawn mowing, the mower is trundled back into the garden shed, and nostrils fill with the sweet scent of freshly mowed grass.

Nothing spells summer with more clarity than such an aroma!

Until you come to understand that such a smell means your grass is in agony. When we are injured, we remove ourselves from the painful situation, make audible sounds of pain, and reach for a bandage. When grass goes through the painfully traumatic process of having a part of it run through a mower blade, it responds with odour. Every time you mow your lawns or have a lawn care expert do it for you; your grass is in pain.

How your grass is is pain

Grass, like you and I, is alive. And, just like you and I, it responds to injury. It has only been in the last 100 years that scientists discovered leafy plants such as grass have self-defence chemicals called Green Leaf Volatiles (GLVs). Those plants release the chemicals when something happens to them. Whether birds are pecking at the grass, or your lawnmower is taking away half its height, your lawn is reacting with its pain response every time. 

Your lawn torture is polluting the air

We’re not about to tell you to stop mowing your lawns. Towns and cities throughout New Zealand would be overgrown and out of control within weeks. But it’s interesting to note that the emission of green leaf volatiles contributes to the world’s greenhouse gas problems, as outlined in a CSIRO and Monash University study in Australia in 1998.

The chemicals are gases such as ethanol and methanol, and scientists believe grasslands throughout the globe are the leading producers of those gas types. As if your mind isn’t blown enough by the fact that lawn mowing contributes to greenhouse gases, the grass also releases oxygenated hydrocarbons. These, which contain alcohol and leaf aldehydes, offer that fresh smell that humankind has appreciated and loved for years.

Why do we love that sweet smell of freshly mowed grass?

You might be uncomfortable enjoying the smell of grass now that you know you’re enjoying pain, but you aren’t the only one. In fact, people swear by the smell for making them feel better and boosting their moods. Why we enjoy it, though, is something that scientists still don’t fully understand. They are, however, willing to give it a good guess.

We aren’t a grass-eating species, so we aren’t enjoying the smell from a hunger perspective. However, the release of the GLVs could make us associate it with the things we do like to eat and drink. This theory was compared to results in a study involving Chinese people and tea. They enjoyed the scent of tea that was almost ready for harvest because it’s something they like to drink. 

We use this information at a near-primal level to ascertain whether something is ripe. Fresh-cut grass is ripe, and we potentially could be drawn to it for that reason. We don’t want to eat it, but we’re affected by it all the same.

When your lawn is torturing you

Lawnmowing season is a great time for many people. You get to be outside enjoying the beautiful sunshine - and hopefully with a book and beverage in hand. Those who hire someone to take care of their lawns will feel more relaxed than most. 

But while you’re breathing in that sweet smell of grass, your allergic neighbour is taking cover. Grass, in general, can bring about wheezing, coughing, sneezing, itching, and general allergy discomfort. 

It’s not the grass, or even the smell, that often causes those allergies to begin with. Sometimes, it’s the blades of the mower stirring up mould, dust, and debris, that lingers in the air. 

Getting rid of grass and opting for gravel won’t solve the problem. Grass pollen can travel for miles, so if your own lawn doesn’t bring on allergies, then someone else’s will. For those who don’t get to enjoy the sweet smell of grass in earnest, it’s worth chatting to your local pharmacist about antihistamines. You can then brave the sunny weather full of confidence and enjoy that pleasant - albeit terrifying odour - like everyone else.