How & When to overseed a UK lawn

How & when to overseed a lawn

When a lawn looks stressed after the Winter it’s easy to think it just can’t be revived. Don’t worry though, there’s a great chance that it can.

Whether you’ve scarified or done a bit of aerating, overseeding the lawn is by far the best option to get it looking thick and lush again.

So, in this article, I’m going through the steps on how to overseed your lawn. Whether doing it in the Spring, Summer or Autumn, you’ll find out how to sort it after scarifying and aerating.

What’s more, find out whether you need to apply a top dressing too.

In the article, I’ll answer some of the most common questions as well as the end-to-end process.

Let’s start with when and how often.

When & how often should you overseed the lawn

On most websites, you will read the best time to overseed is somewhere between Spring and Autumn. I highly recommend doing it in both Spring and Autumn. If you miss the Spring one, then it’s fine to do it in the Summer, just make sure you keep the ground moist if the weather is warm, while the seed germinates.

In England, it’s usually not a problem finding a wet week to sow your grass seed during the Summer.

If you’re planning on top dressing your lawn, more on this below, then it’s best to do it before you overseed. That’s because you can be sure the new seed will hit the soil.

Ultimately by seeding little and often, you will keep the grass more prominent and it will be able to fight off invasion from other weeds and disease.

How to overseed in Spring & Autumn

Whether you’re doing it in Spring or Autumn, the method is by and large the same both times. It just depends on how bad the lawn is at your starting point.

For example, in the past, I’ve scarified twice in March and April, prior to over seeding and then used a 70/30 sand to soil top dressing before overseeding. But, all that isn’t essential if your lawn is already in a half decent shape.

Here are the key steps to take when overseeding the ground in Spring.

Preparing the ground

1. Kill off the moss

You might have been keeping your lawn in good ‘nick’ and don’t have to worry about moss at all. If that’s you, then go straight to the next step. If you’ve got moss, then you’ve got a slightly longer journey than the rest.

I’ve written a full post about how to get rid of moss, so have a read of that too..

Any how, I always recommend using a specific moss killer if you have a problem with moss as opposed to any 4-in-1 product. It just works better, and will hit the moss right at the source.

You can find our fast acting moss killer here. Using this product, you will literally see the moss turn black within a few hours and it will be ready to be scarified after a couple of days

1. Scarify the area

scarifying is super important to allow oxygen and feed products to get right through to the soil and not get blocked off by what’s known as thatch.

I’ve also written a full post on scarifying the lawn, so have a read of that to find out the best way to go about it.

In short, scarifying is the act of going over the lawn with a rake or machine to remove thatch and dead moss.

2. Remove weeds (by hand if possible)

If you don’t have loads of small weeds taking over the area, then it’s definitely best to remove them by hand. Not only would you be avoiding putting pesticide into the soil but you’ll also be able to take the next steps sooner.

If you have lots of weeds and don’t want to remove them by hand, here’s the good news AND bad news

You can apply a weed and feed product which will start working to remove the weeds and help the grass grow.

BUT if you do apply a weed and feed product,. you will need to wait 6 weeks before you crack on with the overseeding. This may or may not be a problem for you depending when you plan to overseed.

Don’t get me wrong I have applied weed and feed products before and just coped with having a bad lawn for a longer space of time than I would have liked but it did help remove the weeds and finished off the moss.

2. Aerate the soil

It doesn’t matter whether you use a weed killing product or remove weeds by hand, you can still crack on with your aerating.

I know I’m repeating myself but I’ve written a full post on how and when to aerate your lawn which you should definitely read if you have time,

Note, this is an optional step when overseeding. If you’re happy with the structure of your soil and you don’t think it’s too dense or drainage is good, then by all means skip this step.

But, if you can at least go over the lawn with a standard pitchfork, it will provide better drainage during the bad weather and help prevent moss.

3. Sow grass seed at a reduced overseeding rate (after scarifying & after aerating)

When sowing grass seed you need to sow at a lower rate than when you’re seeding from scratch. Our grass seed has a recommended rate of 20-25g per m2. But if you just tell us your lawn size, we’ll send you the correct amount, saving you time with too many calculations.

Personally I’d say even if you have patches, you should overseed those again the following Spring (if overseeding in Autumn) or Autumn (if overseeding in Spring)

Choose the grass seed that matches your needs. For example, we sell premium shade grass seed for shady lawns, hard wearin grass seed for lawns that get a lot of usage and

4. Apply a top dressing after seeding (optional)

There are a few benefits to using top dressing on your lawn in the Spring or Autumn- here they are

  • Level out any holes and uneven sections (I have squirrels who love digging into my lawn – soooo annoying)
  • Improve soil to seed contact when you overseed the lawn meaning you have higher success of germination rate
  • Improve drainage especially if you use a 70/30 sand to soil ratio top dressing

A full explanation on how to top dress your lawn is ‘out of bounds’ for this article but there are a few basic things to know.

I recommend top dressing AFTER seeding. That’s how you’ll achieve the best seed to soil contact.

You should apply a top dressing at either 2kg per m2 or 4kg per m2, depending how uneven your lawn is or how bad the drainage is. It may also depend on budget. You could do 2kg per m2 for this overseed, then another 2kg per m2 later in the year or early the following year.

Measure your lawn into segments, for example 6m2 for each segment. Weigh out the correct amount of top dressing.

Sprinkle the top dressing within the measured out area and sweep or rake evenly into the current soil bed.

Try to do the top dressing on a dry day as it will move around the lawn better and fill in any uneven parts.

3. Apply pre seed fertiliser (low in nitrogen, high in phosphate)

This is a must use product when sowing grass seed. It doesn’t matter if you’re overseeding or seeding from scratch – using a pre seed lawn feed will massively increase your chances of success

How to overseed a large lawn

The process for overseeding a large area is the sameas a small area. the only thing that’s different is the tools you use. If the area you’re working with is over 200 m2 then you’ll definitely want to use mostly machinery to achieve the above jobs.

When it comes to spreading either feed, fertiliser or seed, you’ll need to consider a spreader with wheels or a mid-sized hand spreader. That way. you’ll be able to make it so much more efficient – Booyaah!

5. Keep watering for 2 weeks

Oh the watering! You don’t want all your hard work to go to waste just because you sow your seeds and think you can then just watch them grow.

It’s definitely no the case, Well, not quite anyway. If you’re sowing in late Spring it’s likely to be dry – in fact it’s impossible to say isn’t it with our Great British weather.

If it is dry, I’d say to water your seeds for approx 5 minutes per day. If you need to move your sprinkler round the garden to get the whole lot, then simply do it in each spot for five minutes.

Do this twice every day for 2 weeks.

Another tip?

I recommend Watering in the morning or evening. Or at leas in the evening – cos the ground will stay moist because the air temperature cools down over night.

6. Add the finishing touches – STRIPES

Please tell me the reason you want to overseed is to get some beautiful stripes in your grass. Well the final trick to achieving those stripes is soo simple it’s untrue.

ALl you need is a rear-roller lawn mower, thne mow up and down the lawn to and from the direction in which you look at the grass.

That way you’ll be able to admire you work from wherever your are.

This Post Has 2 Comments

  1. Graham Knight

    Great reading, thanks for the advice

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