Garden drainage - grass

Terrontress

I had decking put in a while ago and the drop to the garden was very high so I got 10 tonnes of soil and built it up, the garden is about 2m x 3.5m. I put some sharp sand in but felt like I was trying to save money on soil by bulking it out with sand.

When the grass grew, it grew so quickly. I always had to cut it.

Two years later the grass has all died and the drainage is awful. The soil is surrounded all sides by sleepers so there is no run off. I've bought some new grass seed. Is it an idea to put down a half a tonne of sand and try to rake it in before planting the grass seed?

Any other tips?

Sonnenblumen

Terrontress wrote: »

I had decking put in a while ago and the drop to the garden was very high so I got 10 tonnes of soil and built it up, the garden is about 2m x 3.5m. I put some sharp sand in but felt like I was trying to save money on soil by bulking it out with sand.

When the grass grew, it grew so quickly. I always had to cut it.

Two years later the grass has all died and the drainage is awful. The soil is surrounded all sides by sleepers so there is no run off. I've bought some new grass seed. Is it an idea to put down a half a tonne of sand and try to rake it in before planting the grass seed?

Any other tips?

Sharp sand ( builder's sand?) will actually cause considerable damage to grass and is useless for bulking ground levels. A far more effective solution would be to add a layer (150mm) of 10mm pea gravel. This will provide a more stable sub-base as well as helping to improve the general drainage in the area. All one need's for good grass is 100-150mm of free draining good quality soil, so you can work back from here and do your calculations on where to cut/fill and how much.

Terrontress

Sonnenblumen wrote: »

Sharp sand ( builder's sand?) will actually cause considerable damage to grass and is useless for bulking ground levels. A far more effective solution would be to add a layer (150mm) of 10mm pea gravel. This will provide a more stable sub-base as well as helping to improve the general drainage in the area. All one need's for good grass is 100-150mm of free draining good quality soil, so you can work back from here and do your calculations on where to cut/fill and how much.

I have the level now where I need it though so would I need to dig down 45cm to put this level of pea gravel then put 30cm of soil on top? I don't want to build it up any higher.

macraignil

Terrontress wrote: »

I had decking put in a while ago and the drop to the garden was very high so I got 10 tonnes of soil and built it up, the garden is about 2m x 3.5m. I put some sharp sand in but felt like I was trying to save money on soil by bulking it out with sand.

When the grass grew, it grew so quickly. I always had to cut it.

Two years later the grass has all died and the drainage is awful. The soil is surrounded all sides by sleepers so there is no run off. I've bought some new grass seed. Is it an idea to put down a half a tonne of sand and try to rake it in before planting the grass seed?

Any other tips?[/QUOTE

Soil structure is improved by the action of earth worms and plant roots. Grass roots only grow to a relatively shallow depth so if you want to improve the soil structure in your back garden it might be an idea to plant some deeper rooting plants.

Sonnenblumen

Terrontress wrote: »

I have the level now where I need it though so would I need to dig down 45cm to put this level of pea gravel then put 30cm of soil on top? I don't want to build it up any higher.

45cm of soil is quite deep and you can expect it to subside (variable) in time. Perhaps the best option now is to leave and make adjustments over time as soil levels settle etc. Alternatively you could dig ground and put in a margin of pebble ( 300mm wide x 300mm deep) and top dress with soil. This will provide more surface stability and enhanced ground drainage.