Lawn renovation help

[AgnesSkinner]

We have a north facing garden with a new build (5 yrs old) on clayey gravel that doesn’t drain very well. It is overlooked by 3 storey townhouses to the west and by our townhouse to the south, but the northern end gets a reasonable amount of sun (southern end is slabbed and gravelled).

The previous owners had the garden turfed and the lawn did well last summer, stayed green and dense and we just mowed it regularly.

But, the winter has been really wet here and we have a very high groundwater table, and the lawn is now very soggy and mossy.

Is it salvageable? The grass (what’s left) is actively growing and I’ve just put down Evergreen 4 in 1 to deal with the moss but I’ll need to thicken up the grass - any recommendations? If I do get it back to something near decent what do I need to do during the summer to keep it that way? Aftercut treatments?

Following as our grass needs some help too!

I'm not a lawn expert, but you could try aerating the lawn by poking holes at regular intervals with a garden fork (look up 'lawn aeration' on YouTube) and then brushing/raking across with sharp sand, or a mixture of sharp sand and fine compost, to improve drainage. Before aerating, rake away the moss.

After the frosts, consider sowing some shade tolerant grass seed. Make sure the soil is damp, spread the seeds, rake over a thin layer of compost and tread on it to ensure the seeds have full contact with the soil. Then water with a fine spray so as not to disturb the seeds. Wait until new grass is well established before mowing.

I don't use Aftercut, I just mow frequently at a high setting on dry days, seems to keep the grass happy.

A more radical idea might be to dig a small trench at the lowest point in the garden and filling it with small rocks and gravel, to help drain away water.

Or you could research a non lawn alternative, depending on how you want to use that part of the garden. I've got no experience with this but find idea is attractive.

I've come across using the following instead of lawn: microclover, chamomile (probably needs sun), creeping thyme (sun), Irish moss, creeping speedwell, Liriope muscari, sedum, dwarf cinquefoil.

Thanks lily, we also mow on a high cut but I think we'll try Aftercut if we can get the lawn to restablish.