Topsoil for new turf

Hello all

Last year I received very helpful advice on here after I had inadvertently covered my rear garden with a clay heavy soil while preparing it for new turf.

After that disaster the project was put on hold, and then in the last month I finally got rid of all the soil, 10+ tonnes of it, which was very labour intensive I assure you. But there was no other way.

So now I am starting again, preparing to bring in 10+ tonnes of good topsoil in preparation for turfing in a few weeks. The company that collected all the bad clay soil told me that they also produce topsoil, so I have received a sample and also the inspection report by an independent soil analysis company. It states in it's conclusion : "The sample was described as strongly alkaline, non-saline, slightly calcareous loamy sand with a weak structure and low stone content. The sample contained sufficient reserves of organic matter and major plant nutrients..... To conclude, the topsoil would be considered suitable for general landscape purposes (trees, shrubs & amenity grass), provided the physical condition of the soil is satisfactory and plant species with a wide pH tolerance or those known to prefer alkaline soils are selected for planting, turfing and seeding".

The detail of report shows that the soil has a pH of 8.1. So my question is, as I do not want to make the same costly mistake twice, do you think this soil would be suitable for turf? It is going down on top of chalk, with a small amount of previous topsoil left. I have read in places that turf likes a neutral pH soil of 7, but not sure if 8.1 makes much of a difference or not.

I know there are many threads here discussing soil, but I haven't found one which answers my question, so hopefully you won't mind another one!
And if the above 'premium soil' would be unsuitable, perhaps someone could recommend an alternative.

(Unfortunately I cannot save this post with links as I do not have the authority, so unable to post link to webpage of soil supplier. Site is rbaggregates co uk slash soil)

Many thanks
Damian

 

Like @JWK confirmed, it should be suitable for most types of grass.

If it is a deep layer of topsoil, I would recommend rolling it before seeding. A thick layer of topsoil that is uncompressed can lead to significant lawn issue when it's really wet.

A customer had a somewhat of mansion built and the builders poured on tonnes upon tonnes of topsoil, then seeded. After heavy periods of rain, it was impossible to walk on the grass without your feet sinking about 6 inches into the lawn.

Just something to bear in mind.

 

Thanks for your replies, it has allayed some of my concerns. It is also a good price (£40/tonne loose), which makes a big difference when buying 10 tonnes compared to Rolawn at £100+ per tonne bag. I was also thinking of thinking of using the majority of this soil, and then topping it off with a Rolawn soil, as I think I read on here (or somewhere similar) that grass roots only extend a couple of inches, so perhaps the pH value of this won't be something to worry about.

Mowerman in regard to your comment, the depth of soil reqd ranges from about 10 to 15 cms, so not sure if that constitutes what you call a 'thick' layer? In regard to this, I was also considering putting down some fine gravel first so it's just a 10cm depth all round. Do you think there is any benefit in this?

My main concern based on my previous disastrous attempt is that I want it to be able to drain adequately, as the previous clay soil just had pools of water sitting on the top.

 

May I ask dvs, why did you get rid of the "clay" soil? Clay has more nutrients than any other soil, assuming it was not blue clay. Which is a big no no.

 

Hi, of course but it is a very long story! As I cannot post links yet, it may be easier for you to search posts by me for the full story, I have not posted many. It was that issue which first brought me here.
But essentially I brought a 'recycled soil' in under recommendation, and before I had put any turf down there was a lot of rain and the water was just sitting on top of the soil in huge pools. I didn't want to risk having a continually waterlogged lawn, and so I left it. Again on advice of a gardener, I was told the best thing is to remove all the previous soil and start again, which is where I am now.

 

I've got a book called the Lawn Expert by Dr D. G. Hessayon, which you can buy second-hand on Amazon for under £2.00 + P+P. The later the version, the better.

It recommends a 6 inch layer of rubble over the subsoil followed by a 2 inch layer of small stones (gravel) or coarse sand, followed by 6 inches of topsoil on top. Unfortuately, you may need to do a lot of digging to accomodate this depth. Make sure you break up the remaining clay sods too as they can cause damp or uneven lawn layer issues later on. The bottom surface needs to be even. Also, as it's a clay subsoil, aerate it by stomping on a garden fork to the full depths of the prongs, maybe every foot or so in each area. It also mentions adding lime.

The book suggests firming the soil by walking over it repeadedly in different directions when it's dry and the using a pair of ladders or a large plank tied to a piece of string/rope at each end so that it acts like a handle and pull the plank backwards over the soil to create a level surface. It applies to both turfing and seeding.

Honestly, this book is worth it's weight in gold and I suggest you grab yourself a copy as many consider it to be the 'Bible' of everything about lawns and it may really help you out now and in the future, should weeds and moss take up residence.

 

Thanks for the tip mowerman, I have a copy on it's way to me now.

 

best thing to do is phone a local company and ask for a grade 1 top soil.