Spring Lawn Repair

It is very common to have to repair some lawn areas after winter. This is standard practice on the golf course, and if you have lawns or parts of lawns that recede over winter, re-seeding will be required.

Why does grass thin?

When the conditions for life start to become borderline, 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, or fence on the skyline, and the sun may never get above it for five or six 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 when you thought it couldn't get worse if the winter is mild, you could find moss taking over as the grass keels over and withers away.

Equally problematic, though in perhaps smaller areas, is the summer dieback 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 dieback and thinning

You'll follow the standard procedure for overseeding, which you'll find in the Raking and Scarifying topic. If Moss has moved in, the Moss Control topic would be a better place to be. 

In Summary:

• Remove debris/thatch/moss and open the soil surface by raking or scarifying.
• Overseed 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 these fertilisers.
• Ensure an adequate water supply - in other words, don't let it dry out.

Weed Invasion

The job becomes more problematic if the area has become inundated with weeds. As you will likely be repairing in early spring, most selective lawn weedkillers (safe for grass) will not work. This means manually removing the weeds or using glyphosate, which kills everything, including grass. Glyphosate has no residual effect, so seeding is not impacted. Once the weeds die, which can take several weeks in cool conditions, you can scarify/rake the area and continue as suggested.

An alternative approach is removing the more enormous weeds and manually leaving the rest. Scarifying or raking will remove some leaves from the remaining weeds, allowing a good seed bed. Allow at least two months after seed germination, then apply a selective weedkiller.

What seed is best?

If this is a one-off event due to peculiar weather conditions, then your seed choice should be best for your use rather than worrying about getting 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!

If this is a regular event, perhaps you have buildings or fences that block winter light, or you're in a wet part of the country, then a change of grass variety may go some way to reducing the problem, though be prepared to make this form of lawn repair an annual event! For areas with 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

Due to fences and buildings, these problem areas may not get direct sunlight until May, so 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 usual when temperatures have warmed a little more. Mid to late April is a good target if the weather forecast confirms warming temperatures.

If the area to be seeded is around trees, get on it as soon as conditions improve. 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, it is best to re-seed in spring, as leaf fall will compromise any autumn-sown seedlings.

Preventing Further Problems

Your primary focus should be reducing shade and preventing excess water from entering the lawn. Therefore, where possible:

• Cut back all overhanging greenery
• Can fences be lowered and shade-causing items be moved
• If tree shade is a problem, reduce tree height and open the canopy 
• Prevent rainwater from running off hard surfaces into the lawn

Sometimes, it is impossible to change the environment that causes issues. This may mean living with the problem and, therefore, overseeding every spring.

Follow-on from Summer Drought

Occasionally, after a dry summer, there is insufficient time or resources (hosepipe ban) to repair the lawn before winter. This means a sick, damaged lawn may worsen, with moss and weeds being the main survivors. This doesn't mean you should change your approach to repair, but we recommend reading this article to understand the problem.

Dry Summer Lawn Fix