How To Over Seed An Existing Lawn

Overseeding an existing lawn helps repair worn and damaged patches to give you a thicker lawn. By overseeding with differing grass seeds, it can also help improve the disease resistance of the lawn and improve its overall health. It should be seen as part of your annual lawn maintenance. Browse our wide range of grass seeds here, all of which are ideal for overseeding or sowing a lawn from scratch.

When Is the Best Time to Overseed an Existing Lawn?

• Professional groundsmen and green keepers agree that early spring and autumn are the best times to sow new seed.
• There are two main reasons for this: firstly because the soil temperature should be above the 7°C threshold that most grass seed needs to germinate; and secondly, because there is plenty of moisture (rainfall) about in these periods.
• That doesn't mean you can't sow seed in the warmer months but it will mean that there might be a requirement for you to do considerably more watering if it's particularly dry or warm.

• Avoid sowing if frost is likely. Although a frost doesn't mean that you will lose all the seed, it could certainly reduce the percentage of germination and undermine all your hard work!

Prepare the Lawn

• The main thing to remember when overseeding is that you must try to incorporate the seed into the existing seed bed as much as possible. Scarifying the area, or at least removing any thatch or moss, is vital in order for the seed to get in contact with the soil.
• The biggest mistake you can make is just throwing the seed on the area and expecting lots of lovely new grass to grow as it invariably won't.
• If you don't have access to either root zone (a sterilised mix of sand and soil) or spiking/coring machinery, you can substitute this for some good quality dry(ish) sand to mix with the seed. A 1:5 ratio of seed to sand works well. If you can spike the areas that are barest and in the greatest need of attention, then all the better.

Sowing the Seed

• Mark out a small area and apply the right amount of seed to get a visual reference. Coverage may need to vary slightly in patchier spots.
• It's very important to keep the area moist as much as possible so, if there has been no rainfall for a couple of days, water the area using a fine spray (evenings are always best as this means you will lose the least amount of moisture to direct sunshine).

Aftercare and Feeding

• If you're using our Pre-Seed and Pre-Turf Fertiliser, then unlike with a brand new lawn, this needs to be applied after the grass seed has been sown and when the new grass is up and growing (normally around 2 – 4 weeks after germination). What this will do is boost the root system and help the old and new grass incorporate better, giving you a stronger lawn.
• Any leftover fertiliser can be used a few weeks later to further boost your lawn's health.

Germination and Growth

• The grass seed can take anywhere between 7 and 21 days to germinate, depending on soil temperatures and moisture levels. It can be frustrating waiting for this to happen but as long as you have followed the previous steps then it will germinate. A1 Lawn only provides the very highest quality certified grass seed that has been fully tested to ensure both purity and high germination levels and we select our mixes and cultivars very carefully.
• Leave the area undisturbed for as long as possible (whilst keeping it moist). Give the new seed time to grow and establish as, the better chance you give it in its early development, the better results will be achieved in the long term.

Its First Cut

• When the new grass has reached a length of around 2-3 inches, it's time to give it its first cut. The main thing to note at this point is not to cut it too short. Only take the top inch or so off the tips of the grass and leave plenty of growth as over cutting could seriously damage the new blades and lead to considerable die-back.
• It is also worth noting that there may still be some seed that is waiting to germinate. Over the coming weeks this will lead to the lawn becoming thicker and more lush, so it's worth giving the area a bit of time before you consider going over any remaining bare patches.

Weed and Moss Control

• Even if you scarified the area prior to overseeding, there is still a chance you won't have got all the weeds and moss out of the lawn.
• Don't panic, as these can be treated with a selective weed killer or granular weed, feed and moss killer at a later date.

Need More Help?

If you are looking to sow new seed, feed your lawn or want any additional advice, please browse our handy guides section or get in touch with our friendly team of experts. We are more than happy to provide as much information as you need to achieve your lawn goals. You can contact us by phone on 0800 4118141 or by email at sales@a1lawn.co.uk.