When to reseed a lawn — experts weigh in on choosing the optimum conditions for overseeding bare patches in your grass

Knowing when to reseed a lawn is key to getting the best results. Spring and early autumn are generally considered to be optimum times for new seed to take root in your lawns.

You'll know if reseeding, also commonly known as overseeding a lawn is needed if your grass is looking thin and patchy, or if you've spotted weeds cropping up more than they should.

Aside from knowing the best season, weather conditions, have a huge part to play in finding the right time to sow your grass seed. This includes the day you sow your seeds as well as the following period when your seeds are starting to take root.

Reseeding: Spring vs Autumn

"Early autumn is considered the best time in the lawn care calendar for overseeding due to the warm soil and cooler air temperatures. Early spring is fine for overseeding and sowing grass seed as well but the weed competition is higher at this that of the year," explains Fiona Jenkins, garden expert at My Job Quote.

Graham Smith MCIHort, from LBS Horticulture, also agrees that Autumn is a good time to overseed your lawn if it is looking worn or has suffered from drought over the summer.

"Overseeding in autumn can give your lawn a head start in the following spring, as it will be established enough to cope with the increased use it will see in summer. However, either season (spring or autumn) will work for overseeding a lawn as long as the soil temperature is high enough," says Graham.

Spring and autumn tend to be good times for other lawn care jobs such as when to scarify.

Tom Clamp, head of technical at Doff Portland lists the pros and cons of each below:

• Autumn overseeding
  • Gives new grass plenty of time to establish before winter
  • Less competition from weeds
  • Fewer pests and less foot traffic to disturb new growth
• Spring overseeding
  • A great alternative if you missed autumn
  • Requires more attention, as weeds grow quickly and summer drought can be a risk
  • Popular with homeowners preparing their lawns for summer use

Shop lawn seed for overseeding

Graham Smith MCIhort

Graham has extensive knowledge in the horticultural and gardening industries, and prides himself on using this to help gardeners of all skills create their perfect outdoor space.

Best temperature for reseeding

When it comes to temperature both extreme hot and cold weather should be avoided. Frosts will prevent germination as well as kill emerging shoots. Therefore if sowing in spring Guy Jenkins, Consumer Manager at Johnsons Lawn Seed advises:

"It is better to wait for the weather to warm up and for the sun to heat the ground. It is worth remembering that in sowing terms, the North may be four weeks behind the South due to lower temperatures."

Jamie Shipley, Managing Director of Hedges Direct specifies that temperatures should be above 13 degrees on average before you think about maintaining your lawn.

Guy continues: "Periods of hot sun and warm wind will dry out and kill emerging shoots even if they have been watered the evening before. So if possible, pick a time when it is more likely to be mild and damp, in our climate this is usually more often than we would like."

Guy Jenkins

Guy is the Consumer Manager for Johnsons Lawn Seed, the UK’s oldest provider of lawn seed, and is an expert in the field of lawn seed and lawn care.

Rain and damp conditions

When it comes to water, Guy Jenkins warns that too much is as bad as too little. "The ground should be damp when you sow but not saturated so do not sow after prolonged rain," he explains.

"Drought is to be avoided as the ground is too dry and there is no regular rainfall to water the grass, particularly when it is just emerging from the ground."

It is very important that the new shoots are kept damp whilst they grow. "Rain is ideal, otherwise, a fine spray should be applied in the evening to reduce water loss from evaporation," says Guy.

"This also allows the water to soak down into the soil which encourages deeper rooting grass. If the weather becomes very hot it is possible that the young shoots will be scorched and die even if they have been watered."

FAQs

What is the best month to reseed your lawn?

Graham Smith MCIHort, from LBS Horticulture advises that the best months to overseed a lawn are March, April or September.

"This is because during these months the weather is not too hot or too cold and there is a high chance of rain, which can help to create the ideal conditions for the grass seeds to germinate," explains Graham.

How many times a year should you overseed? 

"As long as you prepare the soil properly, use a high-quality seed, and maintain consistent moisture, one overseeding session each year in spring or autumn should be enough," says garden expert Fiona Jenkins.

If you have large areas of your lawn which have failed, or you want to start over again, have a look at our guide on the best time to lay turf, for a method which yields much quicker results.