Poor Lawn Condition

A few weeks ago I sent this message to the RHS.

In 50 years of gardening I've never come across a lawn like our current one.

We've been here 5 years and for the first 18 months we brought in Green Thumb but their attentions made no improvement. The issues are:

• Most of the grass blades are ultra thin
• The roots don't seem very deep, when using a plastic rake on leaves the grass can easily be pulled out of the ground.
• It dries out ultra quickly in summer
• Border edges are extremely fragile and crumble very very easily.

To give background the house is a barn conversion (converted 1995) and we believe a large part of the garden has old farmyard underneath it. We think the developers covered the concrete with pea gravel. The second owners (circa 2000) created a sunken garden and in doing so spread the soil from their excavations over the gravel and the lawn is living on this relatively thin layer of soil. It drains very well, so no waterlogging anywhere but the lawn does get a lot of moss even were it's in full sunlight. Help!

This is the response I received:

'If there is gravel underneath it is probably thin rooted. Unfortunately the summers we are now having are really affecting the quality of our lawns, many gardeners that like a finer lawn are having problems. It is too late to do any autumn lawn care, however follow our information in the Spring then again in Autumn this should then improve your lawn. Scarify and aerating in the autumn is really important the aerating will relieve any compaction which will make the roots stronger, after top dressing.'

I wonder if the luminaries on here can provide any other insights?

 

Hi and welcome to the Forum.

I think you have answered your own question .


I would dig out some test holes and actually see what you are dealing with a good spade depth .
Look forward to your reply

Spruce

 

I know the lawn condition is poor but I'm not keen to dig a hole in it.

I've used a steel probe and it goes through about 3 ins of soil, then hits about an inch of crunchy gravel before coming up against something solid, which I can only assume is either concrete or centuries old farmyard.

 

You say that your lawn “drains very well” @Steamdrivenandy but “a lot of moss even in sunlight” indicates poor drainage which I would expect with a solid concrete farmyard not far beneath the surface. Without breaking up the concrete and replacing it with a decent layer of topsoil, your lawn is unlikely to improve. That’s a big, expensive job. Perhaps removing the lawn and incorporating some raised beds or large planters to plant some greenery would be another option to consider.

 

The prevalence of moss is one of the oddities I've noted here. Moss proliferates over flower beds as well as the lawn even though it's not shaded and dries out at the mention of drought.
We had to have a 4m tall conifer dropped this Autumn as it had gone completely brown and half a dozen other similar trees are showing very brown branches.

 

It sounds as if any water is pooling above the layers of concrete and gravel during the wet months, causing moss to proliferate, then drying out by evaporation in warmer months, resulting in extreme cycles of wetness and dryness which many plants dislike. In addition to this, due to the lack of soil depth, I suspect that your conifer and other trees have inadequate root growth and poor access to nutrients, causing the symptoms you are seeing.

 

I get the impression the whole site needs looking at regarding soil depth and quality, other wise just go with what you have.

 

If the individual blades of grass are very narrow/fine, it's likely due to the grass varieties used. The ones sold as "luxury lawn" or similar are mostly fine-bladed bents and fescues that are supposed to look better and can be cut shorter but they won't take wear or poor conditions or being left to get longer and then cut - think bowling green. "Utility" grasses (often dwarf rye grass) have thicker blades and will take harder wear, poorer conditions and more neglect.

If there is concrete or paving under there it's probably never going to make a great lawn no matter what grass type you use. Gravel alone shouldn't be a problem as long as it's not the resin-bound stuff that can be used for paving.

 

AFAIK the conifers have been there for about 25 to 30 years and looked fine up until this last Summer when, as I say, one went completely brown. The others looked fine at that time but by early Autumn they too were showing brown limbs. I think the number of trees in the area doesn't help and the last Summer temperatures down at home whilst were were on holiday getting drenched in the Lake District, didn't help.
I suspect that the garden planting has got to an age where the soil water can't support all the mature plants and high summer temperatures worsen the problem.
Difficult to know what to do.

 

Your conifers and other trees will not have enjoyed last summers hot dry weather, also the more unpredictable weather patterns of recent years has stressed a lot of trees and shrubs.
Shallow soil won't help either.
I would investigate soil depth over your whole garden either dig holes or stick metal probe in.
Once you have done that you will be better able to decide what to do, be that switch to containers or break up the concrete to a greater or lesser extent and increasing the soil depth.

 

If it drains well then it may be a old cobbles stones

 

I would do what the RHS recommend. Top dress.
Progressively apply humus rich material* to the aerated grass surface and brush in with a besom broom.Try not to walk upon it when wet, so as to avoid compaction
Allow the grass to grow and mow to a increased length so as to permit more grass leaf to photosynthesise.( Grasses root approximately to the depth of the height of green leaf, as a guide)
Continue this process for several seasons so as to build soil depth . As if you are applying a turf,
one millimetre at a time !
*would source and sieve(6mm) then blend these dry materials : old farmyard manure, leafmould,sharp sand, home compost and perhaps horticultural lime/gypsum/crushed oystershell if ph is low. Apply evenly by hand and then brush in at intervals from Mar-Sept.You will notice increased worm activity, which is a positive. You might brush in any casts if they become unsightly.

 

Thin the soil out even more and have a seasonal bog garden

 

If it drains very well the soil is not clay and there can not be a solid concrete base under the lawn. There might be rubble underneath from demolished buildings containing lime mortar. The lime can push the soil ph above 7.5 making the soil too alkaline resulting in your grass not growing well.