When is the best time to sow grass seed? Lawn expert reveals the ideal time for this task

The varying whims of British weather has changed the times grass can be sown
The varying whims of British weather has changed the times grass can be sown (Image credit: Getty Images)

It doesn’t matter how fantastic your garden design is if your lawn is patchy and bare.

To remedy the problem, it may be tempting to simply grab some grass seed and fling it on the lawn, but there are numerous factors that should be taken into consideration if you want a pristine lawn.

Fortunately, with a little know-how you can get the timing right for this essential lawn task and look forward to a lush, green lawn in no time. 

When is the best time to sow grass seed?

A key part of knowing how to sow grass seed is understanding the best conditions for seed germination. According to David Hedges-Gower, chairman of the Lawn Association, you can germinate seed nearly all year round thanks to the UK’s changing weather patterns, although the species that’s the easiest to germinate will also mean you are destined to seed the same species for years to follow. 

He said: “Seeds require warmth and moisture, so when it's hottest is actually the quickest time to germinate seed, as it’s that heat that swells up the seed pod in order for it to ‘pop’.”

The main species used in the UK – bent, fescue, and ryegrass – all germinate at different speeds and grow very differently indeed, but all grasses need moisture to ensure that seed ‘popping’ occurs. 

David adds: “If you are lucky, nature can do this for us in spring and autumn, depending on where we are in the country. But if we plan to water seeds ourselves, hosepipe bans need to be considered.”

headshot of David Hedges-Gower
David Hedges-Gower

As chairman of the Lawn Association, David Hedges-Gower has a wealth of knowledge on all aspects of lawn care. He is a lawn consultant, author and advisor, frequently working with landscape specialists and professional groundspeople. 

person holding a handful of grass seed

Grass seed typically needs good levels of warmth and water to germinate (Image credit: georgeclerk/Getty Images)

What months are best to put grass seed down?

“The best time to germinate is when nature does it for us, but at times we must intervene," explains David. “There is no such time as perfect, but swelling best occurs when we have warmer temperatures.

“Favourable months can be March all the way through to October, but success takes some careful planning. 

“March and April can be warm or they can can be cold and dry, but often these months are perfect for nature taking care of the watering.

“May, June, July and August are generally our warmest months and, as outlined above, warm temperatures mean warm soils, which means ‘easy’ seeding.”

Sowing different grass varieties

Do different grass varieties have different times to sow? “Essentially no,” says David. “They all require the same things, although the bigger the seed pod, the easier to germinate.

“Ryegrass (a cattle grass) sells well due to its speed of germination, however, it is a seed mix that fails in the UK, creating a commercial success for seed manufacturers and many lawn treatment companies. 

“A grass that is guaranteed to fail, to be replaced by the quick germinating same species, that will also fail,” David adds. “A con? Or just very clever?

“Our countryside is covered in native grasses and the big difference with these species are that they ‘spread’. New plants are created from one single plant (that’s why our countryside is never seeded by anybody yet remains covered in grass all the time).”

You may want to consider versatile and high-quality grass seed blend designed for general-purpose use, such as Ground Master Premium General Purpose Grass Seed from B&Q.


How late in the year can you sow grass seed?

David Hedges-Gower, chairman of The Lawn Association, says there are no hard and fast rules but temperatures above 10˚C are recommended. For this reason, September and October can still be ideal months for sowing grass seed. Natural rainfall often happens, which saves on vital watering, and the soils are still warm following on from the summer months.

Sam Webb

Sam is based in Coventry and has been a news reporter for nearly 20 years. His work has featured in the Mirror, The Sun, MailOnline, the Independent, and news outlets throughout the world.  As a copywriter, he has written for clients as diverse as Saint-Gobain, Michelin, Halfords Autocentre, Great British Heating, and Irwin Industrial Tools. During the pandemic, he converted a van into a mini-camper and is currently planning to convert his shed into an office and Star Wars shrine.