Alan Titchmarsh reveals the 'perfect' length for grass - are you cutting yours too short?

British gardening expert Alan Titchmarsh has shared an expert tip for preparing your garden for spring. One thing you want to get right is the lawn, so before you get the mower out, take note of his advice on the best length to cut grass.

Speaking on an episode of The Gardener’s Year - Early Spring, he gave some specific advice on the best length to mow your lawn. ‘What’s important is you don’t cut off too much,’ he says.

‘It was about three inches, this grass, and I’ve only taken off half that. There’s still about an inch and a half there. It still needs to feed through these leaves, so you must leave it some.’

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So although it might be tempting to really go for it when neatening up overgrown gardens that haven’t been tended for a while, it’s key to leave around 1.5 inches so that the lawn can continue to grow.

‘As the season goes on, you can lower the blades, but do make sure there’s always a good wodge of green leaves on top,’ Alan says. ‘Don’t cut down into that yellow [part of the grass].’

Horticulturist David Domoney, on the other hand, advises cutting grass down to three inches, leaving it much longer than Alan's 1.5 inches. The Royal Horticultural Society suggests a gradual, little-and-often approach. 'For the first mowing in spring, set the cutting height to the highest setting. Thereafter, gradually reduce the height of cut until the desired height is reached. For ordinary ornamental lawns this will be 13-25mm (½-1in) in summer.' The RHS agrees that excessively close mowing can weaken the grass: 'extremely low cutting may scalp the lawn, leaving bare patches.'

Timing is crucial when it comes to preparing your garden for the warmer seasons, and it’s important to wait until the soil has dried out. There’s absolutely no point in mowing the lawn when it’s wet, as this will cause a host of problems and could also be dangerous.

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Does frequent mowing thicken grass?

Mowing can in fact help make grass grow thicker as it removes the tip of the blade of grass. The tips contain hormones that suppress horizontal growth, so regular cutting removes the hormones and helps the grass to spread. It can also make the grass more resilient.

So before you get the lawnmower out, remember not to cut it too low, as although it looks great, you could end up doing more harm than good.