In a nutshell, the best time for most average lawn seeding jobs can be carried out in Spring or Autumn, however, I can tell you that you CAN work this into some other times of the year too, so read on and I will explain.
About me: I have been professionally looking after lawns for close to 20 years. I run an offline lawn care company and have built up solid experience in creating beautiful weed free lawns.
So in short, the BEST times to sow seed would be Spring or Autumn (but there are exceptions which I will mention below).
Why Spring or Autumn?
Well, the two main components we need for seeds to germinate are high enough temperatures and dampness. We also need good seed to soil contact and ideally a topdressing too but that too will be explained further on.
- Spring offers us warmer temperatures (often between 7 and 15 degrees Centigrade (44-59F)), and we still get several spells of rain, as well as morning dew. So it is a good time to do your seed sowing, even more so if you think you will struggle to water frequently requirements.
- Autumn provides similarly good timings for seed sowing in that the temperatures are beginning to ease down from Summer, and the chance of rainfall begins to increase.
I will explain further on how you can sow seeds at lower temperatures, and even during the height of summer. Believe me, I’ve done it both ways with success, so I hope to share this all.
So, we usually need a minimum of 7 degrees C / 44 degrees F for seeds to germinate, and we also need to try and keep the seeds fairly damp for the first few weeks until it has germinated, grown and thickened up.
But like I said above, the are quite a few variables that can be edited and tweaked in the above numbers.
So let’s get started.
Can I sow grass seed in March?
March is certainly a very viable month for new grass to come to life. In fact, if the temperatures are mild there’s every reason to believe that February can also be successful (and yes I have done this with success this year (2020)).
Look at the following lawn I transformed March 27th 2020.
Below you can see pictures of the lawn on April 26th 2020 (just 4 weeks later)
So, moving on from March, it goes without saying that seed should only be put down when the grass is actively growing.
If it is only growing slowly then the seed germination will be slower, whereas if the grass is growing fast then germination can take as little as 3 to 5 days.
Can you sow grass seed in Summer?
The short answer is yes, you can sow grass seed when it’s hot. However, as you might have realized the heat can be an issue that sits on a knife-edge between success and failure.
When sowing seeds at any point during the growing season (March to November typically), you need to try and keep them damp as much as humanly possible. In Summer, the seeds dry out much much faster so much more watering is required.
Applying a wetting agent (like this one on Amazon Uk) would help significantly to retain water around the roots during this time. This is something I do routinely with any seeding jobs.
Thankfully seeds germinate so much faster in Summer than Spring. I’ve personally had seeds start to push through lawns in 5 days, and friends have achieved 3 days, so I can vouch for it working in Summer.
However, you’ve got to water water water.
I’m talking about watering around 5 times a day.
Intense “light mist” watering 5 or more times a day to keep the seeds as damp as possible.
Pop out into the garden every couple of hours to dampen the seeds down (without flooding the area).
If you can’t be there through the day can someone else take on the role? Or if not you may be able to utilize a setup that uses a water timer to allow water flow down the hose pipe 5 or 6 times a day for 5 to 10 minutes assuming the sprinkler reaches all parts of the lawn.
If you need two sprinklers you could buy two hose pipes and two sprinklers and a tap splitter. The water pressure would be less but it may be enough to get you through.
Once the seeds come through continue watering until they are all through and well established, then you can reduce the watering frequency to 3 to 4 times a week, but then using deeper waterings.
Can you sow a lawn in Winter?
In general no.
I have known people fall lucky with milder temperatures, but in general, Winter is the worst time for seeding. The temperatures are too low for germination to happen, and there is a very real risk of frost which can kill a seed right away.
Any other times when you can seed a lawn?
So forgetting about Winter, we simply need a timeframe with minimal risk of frost, and temperatures above 7 degrees C.
There are now available some specialist seeds that can be put down in temperatures as low as 5 degrees.
Using these seeds you can sometimes put seeds down in February, November and December if the outlook appears to be mild for the following few weeks. You do take your chances with this approach, but I know of football clubs using this seed, and also through my own use that this is possible. So for desperate times, this might well be an option for you.
Summary: When to sow grass seed
I would avoid seeding during January. You may get some years that are mild even for several weeks, and you could always give it a try, but the odds are generally against you. Make sure you choose a low-temperature grass seed and try to predict if any frosts are due using various long-range weather forecasts.
Similar to January really. Depending on the weather you could end up with a mild month or one of the coldest months of the year. So if you are in a predicament give it a go, but like January the chances of success are very much reduced.
We are stepping into the good months at this point, however, don’t relax your thoughts and just let loose. There is still a strong chance of Winter to release its forces and wreak havoc on your plans. Just try to study any long-range forecasts before choosing.
If the forecasts seem good, and expected temperatures reach a high of at least 7 and a low of 1 then you are good to go. You should have morning dew on the ground which will help the seed stay damp till midday before you then need to begin watering. If it gets really hot aim for 5 to 6 waterings otherwise 3 to 4 should be just fine. Expect seeds to take around 2.5 to 3 weeks to germinate.
Much the same as April. Try to keep up consistent 3 to 6 times a day with watering. Expect seeds to take 2 to 2.5 weeks to germinate. There will still be some morning dew, but I’d also make sure that you water first thing as well.
June, July, August
Traditionally the 3 hottest months of the year. There is a risk of seeds not germinating if you don’t water “a lot”. It is critical for the seeds that you water very often and very very regular. Ideally every couple of hours. Thankfully the extra work will reward you with quick germination. Expect seeds to take anywhere from 5 days to 2 weeks to germinate and pop through the ground.
A very good month for sowing seeds. The temperatures are now not so hot, and there is a chance of rainfall. The main thing at this time is to keep up with a solid watering schedule. I would personally continue with 5 to 6 times a day. Expect seeds to germinate in around a week or 2.
As things cool down so does the rate at which grass seeds germinate. So expect slower germination but you still need to aim for a good watering schedule. Water 3 to 5 times a day, and expect to see new seedlings appear in around 2 weeks or possibly less.
November, December, January
These are literally the cooling down months heading into Winter. As you move through these months the longer you leave it, the less chance of success there will be. The temperatures will continually be getting low. There will be the risk of failure if a frost occurs, and there is always a risk of snow. Expected germination would be around 3 weeks IF mild weather happens, and you get a lucky few weeks break from frosts. Personally, these months offer lower chances of success close to minimal.
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