I received this question in January 2018 by a reader Mike, who asks about his town house lawn.
I have just moved into a town house with a north facing back garden. The soil in the back garden has a lot of clay.
The current grass is not doing well, and the ground is very soggy, wet, and soft under foot. The grass is thinning out.
Can you recommend a suitable grass that I can replace the existing grass with? Is there any benefit in digging out the current clay soil and replacing with something that can drain better?
Thanks for the question Mike.
Your problem may be more serious than the wrong type of grass. Trying to grow a lawn in the shadow of a north wall is very difficult.
I receive a lot of enquiries from customers who believe that grass is able to grow anywhere. Unfortunately this is far from the truth. In nature, grass grows in vast open plains. Bathing under unbroken sunshine from dawn until dusk. It has evolved to thrive in a full sun aspect.
Grass species development experts have worked hard to create varieties which tolerate shade. There are, however, varying degrees of shade. Light shade under a tall tree is very different from deep shade in a small back yard.
Even shade tolerant grass needs to see direct sun a few hours a day to thrive. A town house lawn behind a north wall will only see direct sun in the middle of the day in mid summer. If you also have high fences or tree coverage that will also lessen the amount of light reaching the grass.
Adding to this low-light problem is a waterlogged, clay soil. Grass can tolerate some waterlogging, as long as it is temporary. A heavy, dense soil and bad drainage all year round is bad news for grass.
Growing a town house lawn
But what can you do? Your priority is to improve the growing conditions for the grass. Install drainage to give the water somewhere to go. Improve the quality of the soil by hollow-tining and top dress by brushing in a round-grain sports sand. This will help the movement of the water through the soil. Improving the growing conditions will give the lawn the best chance of survival.
As for grass seed, look for a shade-tolerant variety or a modern amenity grass mix. Have a chat with Hurrells who are grass seed experts. They will be able to give advice on the latest strains. Sow in early spring and it should look great for summer.
You may need to repeat the “improve drainage and reseed” process every year to keep a lawn going. Keeping a lawn through the winter in such difficult conditions maybe a bit much. But it is worth trying and not expensive.
If the grass continues to fail after all this effort then lawn is not the best idea in that spot.