So you’ve done all the work;
You’ve chosen the best lawn seed for the job, prepared the ground perfectly, you’ve sown the grass seed and you’ve been watering diligently every day.
And for the first few days, you see nothing.
Frustrating isn’t it!?
So it raises the question, ‘How long does grass seed take to grow?’
Well, you should see signs of germination and growth within 10 days when conditions are ideal. Within 8-10 weeks, you should have a fully established lawn which you can use.
However, conditions are rarely ideal so the answer is a little more complicated than that.
What Affects Grass Seed Germination?
If you planted the same grass seed on the same day every year, results would vary. They would never be the same.
The speed at which your grass seed germinates and grows depends on four main factors which you must understand if you want the very best results.
- The Weather
- Soil Conditions
- Grass Types and Seed Mixtures
We’ll look at each one individually.
The weather plays a huge role in how quickly grass seed germinates and grows. So, you must do it during the seasons that’ll provide the best growing conditions.
Most grass types germinate when temperatures are consistently above 8-10 degrees. If the temperatures drop below 8-10 degrees regularly, it’ll slow down germination and growth.
Grass seed also needs a balance of constant moisture without being drowned in water. If the ground is hot and dry, the seed will essentially bake and die. On the other hand, if it’s drenched with water, chances are the seeds will rot.
The seasons which provide the closes to ideal growing conditions are autumn and spring. With autumn being the best time to sow grass seed.
However, just because these seasons providing the closes to ideal growing conditions, doesn’t mean they are ideal. For example, if spring is unusually dry, you aftercare needs to be excellent with the provision of water etc.
When deciding when to sow grass seed make sure you have a look at a two-week weather forecast first to try and pick a window that’ll provide the closest to ideal conditions.
Soil conditions should also be as good as they can be.
Firstly, the soil needs to be firm but not compact, free of weeds, moss, rocks and roots. It needs to be rich in nutrients from the addition of a pre-lawn feed and/or organic matter and have the correct pH balance for the types of grass you’re trying to grow.
All of this should be addressed when you prepare the ground for seeding.
The soil should also be warm enough to facilitate germination. This is one of the reasons why autumn is the ideal time for sowing new grass seed. The summers sun will have warmed the soil, making it the perfect temperature for germination.
Also, how deep you plant the grass seed will have an impact.
If you plant it too deeply, it won’t get the sunlight it needs. If it’s too close to the surface, it won’t have sufficient contact with the soil.
Grass Types and Seed Mixtures
Different types of grass germinate and grow at different rates depending on the weather, soil temperature etc.
As you can see in the image above provided by Barenbrug shows the different soil temperatures that different grass types germinate at.
As you can see, hardwearing Ryegrass germinates at lower soil temperatures of around 8 degrees which means you can sow this type of seed earlier in the spring and later in the autumn when temperatures are cooler.
However, Fescues require temperatures of around 12 degrees and Bent grasses require soil temperatures of around 15 degrees in order to germinate reliably.
That means if you want an ornamental lawn you’d be better sowing in late spring and earlier in the autumn when temperatures are high enough.
Many types of grass seed mixtures contain a mixture of Rye, Fescue and Bent grasses. The first signs of early germination will always most likely be the Rye content with the Fescues coming next and the Bents germinating last.
This is often why your lawn looks patchy after a couple of weeks.
The key is to keep up with your aftercare.
This can make or break your lawn.
Really the only thing you need to do with your newly sown grass seed is to water it.
However, this is a balancing act.
The key is to keep the soil moist and prevent it from drying out. But don’t water too much and have the grass seed lying in puddles of water.
Watering twice a day in the morning and evening for around five minutes each time should be enough to keep the soil damp without soaking it.
In dry conditions, you might want to water in the middle of the day too as long as it’s not too hot.
Don’t water if it rains as the ground will become too wet.
How to Speed Up Grass Seed Germination
Of course, there there is something you can do to speed up the germination of grass seed and that is to artificially increase the soil temperature
In order to do this, you’ll need some clear, heavy-duty plastic sheeting.
Cover your lawn with it and the plastic will let the sun through an keep the heat locked in, creating a greenhouse effect which raises the soil temperature.
Remove it to water the ground in the mornings and evening and replace it once you’ve watered.
As the soil temperature rises you’ll see the grass seeds start to germinate and grow at a fairly quick rate.
You could also pre-germinate your grass seed prior to sowing it which will give it a head start.
As you now know, grass seed germination time depends on several factors.
Many of which you can control.
As a result, more often than not, grass seed fails to germinate as a result of the gardener doing something wrong. Either poor preparation, sowing seed at the wrong time, poor aftercare or a combination of all three.
However, if you choose the right type of seed, prepare the ground well and look after your new seedlings properly, there’s no reason why your lawn should fail.