Slightly raising level of a section of existing waterlogged lawn?

itfdlk

I had a bed of stones removed from the back garden last year and replaced the area with topsoil, which I then seeded with grass. I was a bit concerned that the level of the topsoil should be a bit higher, but daftly listened to the "It'll be grand" chap who spread it for me.

Well, the grass grew, but the ground is clearly slightly sloped, gets waterlogged in parts and is looking sorry for itself. I now want to raise the level of that lawn area about 3 inches so that it's even and won't act as a swamp.

Is either of these methods advisable?
1. Chuck more topsoil on top of the lower areas, level it out and sow more grass seed.
2. Hack off the top layer of the existing grass, add top soil, level it out and set the grass sods back on top of the soil again.

Ideas, experiences or advice, anyone?

macraignil

Stones are good for drainage in soil so getting them removed would probably have contributed to the drainage being a problem now. Adding more topsoil is unlikely to improve drainage. I don't understand why you would need to remove stones from under a lawn but seeing that its already done either method you mention could be used to change the level.

I had to improve an area of lawn in my parents garden last year when they got a digger in to remove an old hedge that had died back and at the same time removed a vegetable patch and some fruit bushes in the middle of the lawn area they wanted to keep as lawn again. They should really have just got the digger to level off the area better in the first place but it was not too much out of line so I simply spread standard potting compost in the areas that were lower than the rest to make it even and spread some leftover grass seed after I dug out the weeds and loose stones that were sticking up and being a problem for the lawnmower. Organic material like potting compost is said to help form a better soil structure that allows better drainage. The lawn area was significantly better after the treatment described in just a few months of regular mowing.

If I was approaching the situation you describe I'd be more inclined to get some cheap compost to spread into the lower parts of the lawn and maybe use a fork dig into and loosen the soil where it might be compacted. If you only put on a relatively small amount of compost at a time the grass should grow through so you might not even need fresh grass seed (I just had some leftover from planting my own lawn). Some grit might be helpful for the drainage as well but you would have to avoid leaving this near the surface and interfering with mowing. Its been a very damp few months with no opportunity for soil to dry out throughout the country so it might look worse than it actually is at the moment and improve a bit anyway over the next few months.

Lumen

Another option is to put narrow drainage channels in to take water from a local low point to somewhere else.

Dealing with drainage from the top seems unlikely to work. If you add free draining material the water will just percolate through that, pool where it is right now and then rise back to the surface.

Like putting compost into your cold water tank, you'll just have wet compost.

macraignil

Lumen wrote: »

Another option is to put narrow drainage channels in to take water from a local low point to somewhere else.

Dealing with drainage from the top seems unlikely to work. If you add free draining material the water will just percolate through that, pool where it is right now and then rise back to the surface.

Like putting compost into your cold water tank, you'll just have wet compost.

In the area of replanted lawn I improved last year, the compost was only visible for a few weeks and the whole area now just looks like standard lawn. I think the earth worms in the soil bring the compost deeper into the ground over time thus improving the structure further down and the grass would also cover it as it grows. Can't tell from the original post just how bad the drainage is and I agree digging proper drains would be more effective but at the same time might be taking on more work than is needed if the ground is just a bit uneven and waterlogged because of the continuous rain for the last six months.

itfdlk

Thanks for this useful feedback and your experiences!

To clarify, the stones were not under a lawn - the area in question was a large bed separated from the main lawn by a path. It was covered in gravel-type stones, which were a curse to keep clear of weeds, so I wanted to make it all lawn. Unfortunately, it has since become clear that the level of the grass is a couple of inches lower than the path.

I considered a small drainage channel, but there is nowhere for the water to drain to - you'd have to go a mile in any direction before finding even a gentle incline Maybe I'll dig a hole in the worst corner and put some stones in there to encourage downward draining.

I see Lidl have cheap peat-free compost at the moment, so I might stock up on that and try macraignil's fix!

macraignil

itfdlk wrote: »

Thanks for this useful feedback and your experiences!

To clarify, the stones were not under a lawn - the area in question was a large bed separated from the main lawn by a path. It was covered in gravel-type stones, which were a curse to keep clear of weeds, so I wanted to make it all lawn. Unfortunately, it has since become clear that the level of the grass is a couple of inches lower than the path.

I considered a small drainage channel, but there is nowhere for the water to drain to - you'd have to go a mile in any direction before finding even a gentle incline Maybe I'll dig a hole in the worst corner and put some stones in there to encourage downward draining.

I see Lidl have cheap peat-free compost at the moment, so I might stock up on that and try macraignil's fix!

Thanks for clearing up what was done in the garden as I picked up on what you were saying incorrectly. If the area was covered in gravel then it would have been standard practice to put in a weed suppressant membrane under the gravel. Was this removed when the gravel was taken away?

If it was still there and has been for some time it might be clogged and contributing to poor drainage. If you dig the soak-away area you describe it should become obvious fairly quick if this is the case. If there still is a weed control membrane under the new lawn area it might be best to remove it even if it sound like a lot of work as it could continue to be a problem for the area having a natural soil structure.

itfdlk

Luckily, the membrane was definitely take up along with the stones - so that's one issue I don't have!

looksee

Was the soil under the membrane dug before adding the topsoil? It may have created a 'sealed' layer under the topsoil.

itfdlk

No, it was not dug. It was pretty compacted, too, because of the stones. Good point.