Saving a new lawn

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Hey guys,

Title is a bit extreme, but I think I've royally f*cked up part of the prep for a new lawn as a result of time pressures and the weather and I'm clawing to anything not to rip it up.

It's a narrow strip across the back of the house that was on a good slope (dropped 500-600mm over 5m). I built a retaining sleeper wall across the length approx 18m long, backfilled behind it with gravel (5-6 inches) and geotextile and dropped a land drain at the bottom of the gravel to create an equal void and distribute pressure across the wall. The width is now around 4.5m from front to back.

In order create that drainage channel I used old grass blocks I've dug up in other areas like bricks and that seems a good solution at the time to retain the gravel.

The rest of the back fill has been spoil (2x grab) and top soil (1x grab) although I am beginning to suspect that quality of the top is poor and its holding alot of water.

The weather has been crap, so the prep/compaction of the top soil layer was very poor (no chance of getting my compacter on it) and the turf turned up on Friday. Felt a little pressured to get it down Saturday when the weather was good but I now know I would have been OK to leave it until Sunday/Monday (contrary to what everyone was telling me). I think this day of lost prep cost me big time

I've never done this before so I gathered some help to get it down on Saturday but given everything I had put down was sodden I didn't really see another choice but to go over it with dry soil and compact as well as I could with a 3m soil pipe to at least get it flat with a small drop to the back.

Since Saturday we've had two days of moderate rain and I've been watering it for an hour each morning.

However, the top layer of soil (4-5inches) almost feels fluid underneath so any sort of weight not on a couple of long boards is moving everything around. I can't see how this will rectify itself when the roots establish. So far the grass itself seems to be doing well and there is no visible waterlogging on the surface.

I think this is a combination of everything really:
* Top soil is not great quality holding too much water
* Not enough compaction by myself
* Maybe should have installed some land drains perpendicular to the wall

Is there anything I can do to help the situation without ripping it up?

I don't want to wait 4 weeks and find out things havent improved and run in to winter with a mess, but I'm not very confident that things will get better naturally...

Some ideas I've had:
* Continue rollering every few days with the drainage pipe. Its light that it wont stress the grass too much, but will compact it by maybe 10-15% and keeps the surface flat
* Drill some bore holes in the back of the retaining wall and insert perforated drainage pipe (40-60mm) every 3/4m so take some excess water out of the ground. Wont be able to wrap the pipe in any geotextile but needs must
* Cry

Thanks for any input
 
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I'm taking it that you dumped a load of soil onto some ground and then put some turf on top of that /

What was the ground like you put the soil onto ? did you dig it over loosen it up first?
what depth was the soil?

If the ground you dumped the soil on is super compacted then the water can't get away, re lift the turf loosen the ground up to at least a foot in depth then relay the turf
If the sub base was reasonable and well draining then just leave it alone, and stop rolling it, rolling wet ground is disastrous you will compact it further squeezing all the air out and that would not be good at all. Don't even walk on sodden wet ground. Just let wet ground dry naturally and let gravity take care of any loose compaction, the worms will bind it all together, keep off it until after the winter.
 
I'm taking it that you dumped a load of soil onto some ground and then put some turf on top of that /

What was the ground like you put the soil onto ? did you dig it over loosen it up first?
what depth was the soil?

If the ground you dumped the soil on is super compacted then the water can't get away, re lift the turf loosen the ground up to at least a foot in depth then relay the turf
If the sub base was reasonable and well draining then just leave it alone, and stop rolling it, rolling wet ground is disastrous you will compact it further squeezing all the air out and that would not be good at all. Don't even walk on sodden wet ground. Just let wet ground dry naturally and let gravity take care of any loose compaction, the worms will bind it all together, keep off it until after the winter.

The subsoil (the contents of 2x grab lorries) was not compacted very much at all on purpose. Barrowed, raked roughly level and a light compaction (25kg whacker plate).

Before laying the topsoil layer this subsoil was soft under foot after rain and seemed to drain off fine.

The topsoil was barely compacted due to inclement weather (just a light roll with the a soil pipe). I've given it once light roll after laying the turf. The depth of this layer is approx 4-5 inches.
 
The subsoil (the contents of 2x grab lorries) was not compacted very much at all on purpose. Barrowed, raked roughly level and a light compaction (25kg whacker plate).

Before laying the topsoil layer this subsoil was soft under foot after rain and seemed to drain off fine.

The topsoil was barely compacted due to inclement weather (just a light roll with the a soil pipe). I've given it once light roll after laying the turf. The depth of this layer is approx 4-5 inches.
I would just leave it alone then, let it settle itself. Grass is difficult stuff to kill.

When ylou say 'drain off fine' do you mean run over the surface or soak into it?

Unless your top soil was a clay type, the fact it is holding water may well be a sign of good fertility, plenty loam in it.
 
I would just leave it alone then, let it settle itself. Grass is difficult stuff to kill.

When ylou say 'drain off fine' do you mean run over the surface or soak into it?

Unless your top soil was a clay type, the fact it is holding water may well be a sign of good fertility, plenty loam in it.

Theres only a slight drop (it is meant to be flat) but so now drops around 1 inch over a 4.5m run. I guess what I meant was that there was no visible pooling aside from where i had walked over it and left some foot prints.

The dog did get on it this morning (has been fenced off but he found a hole) and left a good couple of his own footprints in the turf. Am I best to lift and drop some more soil in to bring it back level?
 
If the new turf has only been down a week, roll it back up in a section and find for sure what is causing this movement under the roll of turf. It shouldn't have rooted much in a week, esp if the soil is as soft and loose as you presume underneath.

If you think it's because it's not compacted enough underneath then you may be able to roll the whole lot up carefully and sort out the soil underneath. Just don't leave the turf in a roll too long.

One thing I will say though, when we laid our lawn last year we compacted it too hard imo, as my better half was paranoid about an uneven lawn. A year later, there are a few patches where the grass hasn't rooted. I daresay there's a happy medium that grass loves :)
 
I wouldn't worry, and I certainly wouldn't compact any more.

If it's sodden, then don't water.

Worst case scenario is that the lawn sinks a little and is a little uneven - you can sort that out with topdressing once it's settled.

...and best to avoid the dog peeing on the lawn!
 
If the new turf has only been down a week, roll it back up in a section and find for sure what is causing this movement under the roll of turf. It shouldn't have rooted much in a week, esp if the soil is as soft and loose as you presume underneath.

If you think it's because it's not compacted enough underneath then you may be able to roll the whole lot up carefully and sort out the soil underneath. Just don't leave the turf in a roll too long.

One thing I will say though, when we laid our lawn last year we compacted it too hard imo, as my better half was paranoid about an uneven lawn. A year later, there are a few patches where the grass hasn't rooted. I daresay there's a happy medium that grass loves :)

I wouldn't worry, and I certainly wouldn't compact any more.

If it's sodden, then don't water.

Worst case scenario is that the lawn sinks a little and is a little uneven - you can sort that out with topdressing once it's settled.

...and best to avoid the dog peeing on the lawn!

A small update. I went ahead and installed some land drains over the weekend, making sure that no part of the lawn was > 2.5m away from one. Given the conditions I only went down to around 300mm, gravel and 60mm perforated pipe wrapped in geotextile with 100mm of topsoil back on top. The pipes run through the wall as opposites to draining down behind it.

I'm not expecting to see any benefits of this just yet.

I am fairly confident the level of compaction is not adequate given the rain pre-installation in place so I am weighing up whether or not to use this week as its dry to roll up each row and add more topsoil to try and give it a bit more stability under foot. I should not be sinking like I am right now.

The sod is still in good condition and hasn't quite rooted too deep yet so its an option thats still on the table.

@StephenStephen I would like to wait but we have dogs and going in to winter without any where for them isn't much of an option for us.
 
The irony is that the two spare rolls ive left out are still alive and well. Last time I listen to sales reps telling you to get it down ASAP. Probably going to end up f*cking about with this until the end of the month.
 
I ran a bit of an experiment this evening to at least try and formulate a plan...

I'm trying to describe the soil...almost liquefied is probably the best description. I rolled back one section and add a whole gorilla tub of dry top soil on top and walked it down. The new soil compacted but underneath the entire layer feels fluid so it doesnt feel stable still and now im about an inch higher than where I was. I'm going to check it in the morning and look for some answers.

One option is to forget adding more top and add grit sand or some other substance with high drainage properties and structural strength. I know it will hurt the soil but if it improves stability then it might be a case of needs must.
 
Time to leave it alone. It wont firm up until the grass roots penetrate into the top soil. Post #5 is right.
 
Time to leave it alone. It wont firm up until the grass roots penetrate into the top soil. Post #5 is right.

It's an option, but I can't see me being able to even walk on it until the Spring so its a last resort and if I have a small window to do something now (weather is good all week) then I will.

I run some more experiments on the soil this morning and took some of the stuff thats fluid and added about 25% grit sand to it. Obviously it dried it a little bit but the biggest change was it stopped it clumping together

I put around the same amount untreated and treated with grit sand in a dog bowl to see if it effected compaction/structural stability and it seems to be a noticeable improvement. To what effect this would have on soil nutrition then I don't know, but I can always treat the soil from above.
 

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