Suggestions on how to 'fix' a new lawn?

A year after it was laid around a new build the lawn is in serious decline inspite of spring feed (and light spring scrification owing to surprising build up of thatch). The recent photos of the soil profile show (hopefully) that the turf was laid on a layer (maybe 4") of 'compost' directly on top of your usual compacted layer of clay and stone.

The turf seems to have totally exhausted the compost (recent proliferation of Black Medick) and the roots arent making much progess into the subsoil. So a number of questions:

Would you normally rotavate organic matter to a prescribed depth into your newly made ground or just layer it on top?
Is there a standard depth recommended?
With such a definate boundary between organic layer and subsoil (almost like being in a pot) do I carry on feeding or start again
Have the landscapers done anything 'wrong' or is it just to be expected with new build?

Any recommendations appreciated (it does seem to have been a stressful spring for lawns around Bristol generally unless its something I'm doing fundamentally wrong!)

A year ago:

Don't assume that when it's put down its all fine. Landscapers....landscape. Caring for a lawn full time is something else and not too many will be thinking this ( apologies if this offends some)
Was it well glyphosated before hand? Was it left to fallow? Was it then glyphosated after that? ( weeds coming through already point to.....NO)

Why anyone would use compost is beyond me...or anyone who knows lawns.....its compost....for gardens etc.....

As Louise points out, it's hopeless for growing long term....

Many landscapers, from my experience tend to use a fine finished product to get decent levels, sometimes just because it looks good.

Root development is struggling too.

Lawn is also extremely hungry too.

Ryegrass lawns need more food....period and a spring feed would have gone out through the profile some time ago.

Feed now....straight feed, nothing with Iron ( unless under 2%) for colour up.

Then fed again in autumn and even in winter with this type of grass.

Then aerate, aerate, aerate.

Every new lawn ( they're not new if you think about it) should be aerated after about 4-6 months ( weather permitting)

Lawn also appears to have red thread scars or even poor mowing scars ( have you sharpened the blade in the last week or two?)

Other than that, buy my book to give you a year round idea......

Replies

PRO Supplier

Progreen Weed Control June 19, 2015 at 12:31pm

a real 'before and after' !

If a spring feed has had no noticeable signs of improvement it indicates to me there is something in the soil profile that is stopping the chemical exchange and the ability of the roots to absorb nutrients in their preferred form.

I wouldn't normally advise laying a lawn on pure compost as its so light with no body - but also becomes water repellent after a while. It could be rainfall is draining through the compost without absorbing it (repellent) and so not giving time for the chemical exchange within the soil (requires moisture). Use a wetting agent such as H2Pro to improve moisture retention and the roots should chase it growing longer. Combine with a decent fertiliser (preferably long lasting/ slow release)

The lawn looks worse on the lower areas...? Could be a drainage issue too with the water being held up by the clay on the lowest part of the lawn and killing the roots but the depth of compost makes that less likely..

Richard@Progreen
(01778) 394052
- Gareth > Progreen Weed Control June 19, 2015 at 5:03pm
  
  The compost becoming water repellent is a possibility. I'm trying to track down what the original 'compost' was - all I can say is that was/is very fine, high in organics, dark in colour that has reduced in volume considerably.
  
  Drainage is an issue as the clay layer is impeding drainage in places.
  
  I shall look at wetting agents - never used them before
David Hedges-Gower June 19, 2015 at 2:01pm

Don't assume that when it's put down its all fine. Landscapers....landscape. Caring for a lawn full time is something else and not too many will be thinking this ( apologies if this offends some)
Was it well glyphosated before hand? Was it left to fallow? Was it then glyphosated after that? ( weeds coming through already point to.....NO)

Why anyone would use compost is beyond me...or anyone who knows lawns.....its compost....for gardens etc.....

As Louise points out, it's hopeless for growing long term....

Many landscapers, from my experience tend to use a fine finished product to get decent levels, sometimes just because it looks good.

Root development is struggling too.

Lawn is also extremely hungry too.

Ryegrass lawns need more food....period and a spring feed would have gone out through the profile some time ago.

Feed now....straight feed, nothing with Iron ( unless under 2%) for colour up.

Then fed again in autumn and even in winter with this type of grass.

Then aerate, aerate, aerate.

Every new lawn ( they're not new if you think about it) should be aerated after about 4-6 months ( weather permitting)

Lawn also appears to have red thread scars or even poor mowing scars ( have you sharpened the blade in the last week or two?)

Other than that, buy my book to give you a year round idea......
- Gareth > David Hedges-Gower June 19, 2015 at 5:14pm
  
  Thanks David - I have your book. Whilst landscaper baiting is one of lifes great pleasures I havent gone down the road of blaming them yet. The weeds are seeding in the open turf not growing through from any sub layer so its not an issue with a seed bank. Glyphosate can be residual in some soils so I would be reluctant to lay turf on soil with any herbicide in?
  
  It has had red thread (poor mowing scars - steady on!). I associated it with the excessive N and lush growth that it showed last year.
  
  See Louise reply re compost.
  
  Feeding is the current on going plan - a 4-3-2 organic feed which gives a long term slow release and none of the damaging excess top growth with high N feeds.
  
  I hadnt thought of aeration being an issue - hollow tine or slit tine?
Graeme @ BGS June 19, 2015 at 7:59pm

Certainly looks like poor prep work. From your picture with the lawn looking lush, I assume that this was rapid grow due to high N treatments (was this the little N bombs that G Thumb use?). Hope you were not mowing it at that level of growth every visit?

Two options really, start a fresh or move into lawn recovery mode but this will be an ongoing challenge and not instance, I always tell my clients that lawn recovery is like making love to a beautiful lady, some things just can't be rushed!