Spring Lawn Repair
It is very common to have to repair some areas of lawn after winter. This is standard practice on the golf course and if you have lawns or parts of lawns that recede over winter then re-seeding will be required.
Why does grass thin?
When the conditions for life start to become borderline then the lawn will thin as individual grass plants die. This usually happens over winter when the total amount of sun light reduces considerably. Throw in a building, tree of fence on the sky line and the sun may never get above it for 5 or 6 months leaving areas of lawn in permanent shade and dampness.
Some winters can be cold and dry which means more light than average so the damage is not too bad. If on the other hand the winter is cloudy and wet you'll have double damage from less light and possibly drowning grass plants. And just when you thought it couldn't get worse if the winter is mild then you could find moss taking over as the grass keels over and withers away. The extreme effects of this combination of weather conditions can be seen in the image. This occurred over December and January 2015/16 and again 2019/20.
Equally problematic, though in perhaps smaller areas, is the summer die back usually around trees when leaves block out the sun and the tree roots suck up all moisture from the soil leaving nothing for nearby plants including the lawn!
How to repair seasonal die back and thinning
You'll pretty much follow the standard procedure for over seeding which you'll find in detail on the next page and in the Raking and Scarifying topic. If moss has moved in then the Moss Control topic would be a better place to be.
- Remove debris/thatch/moss and open the soil surface by raking or scarifying
- Over seed the whole area so the new seed blends with the existing grasses
- Ensure good seed to soil contact
- Fertiliser - if this is part of an established but thinned lawn you are best off with one of the fertilisers at the bottom of this article
- Ensure adequate supply of water - in other words don't let it dry out
What seed is best?
If this is a one off event due to peculiar weather conditions then your seed choice should be what is best for your use rather that worrying about getting a grass that will survive in damp shady conditions. The chances are it won't happen again (not for a while anyway) and if the summer is hot and dry you'll have to re-seed yet again!
If this is a regular event; perhaps you have buidlings or fences that block winter light or you're in a wet part of the country then a change of grass variety may go someway to reducing the problem though be prepared to make this form of lawn repair an annual event! For areas that have good moisture most of the year (usually around fences and buildings) use Shadygreen grass seed. For areas that go from shady damp in winter to dry in the summer use Staygreen grass seed.
Timing is important
These problem areas may, due to fences and buildings not get any direct sunlight until perhaps May which means soil temperatures will be lower than the rest of the garden. Therefore don't seed too early and perhaps start a week or two later than normal when temperatures have warmed a little more with mid to late April being a good target if the weather forecast confirms warming temperatures.
If the area to be seeded is around trees then get onto it as soon as conditions come right as you'll want to have your newly seeded areas well established before the tree canopy fills out. If your problem is around trees but at the end of summer then best re-seed in spring as leaf fall will compromise any autumn sown seedlings.