How to improve drainage?

[NanooCov]

We just moved into out new house at the beginning of December (hurrah!) but with all the rubbish weather we've been having it's become clear that the drainage in the garden is terrible (boo!). We have a quagmire of a lawn and lots of puddles in the flower beds (and some rotting plants). This isn't exclusive to our garden - speaking to the neighbours (and noseying in their gardens from our upstairs windows) they have similar puddles, mossy lawns and loads of worm casts. We don't appear to have the worm casts just yet.

Any advice on improving drainage long term? We accept it's going to be a big task but as the house doesn't need too much done, we're ok with that.

For info, we have a patio immediately out the back door, then a big lawn with beds down either side mostly planted with shrubs and a few roses) and a pond (which has been done badly and has a liner that is perishing so will have to deal with that anyway), then decking at the far end beside the shed. We also have cobnuts and crab apples at the far end.

Thanks in advance for any suggestions.

NanooCov, it sounds like your area has a clay based soil and if so then it is typically slow at draining. You need a 'Soak away' digging...

What I did was dig down through the clay until I hit sand (I live near the coast). I dug a hole which, due to being about 6 feet deep to get through the clay, ended up being the size of a wheelie bin to stop it collapsing in on itself. I then bought about a cubic metre of "Rejects" (large 40-75mm) sized pebbles and filled the hole all the way to the soil level and effectively created a drain point for my lawn. The finished hole was about two feet square at the top but only about 8 inches square at the bottom so it gradually tapered as it got deeper.

Just a few of points to note:

You may not hit sand but once you get down through the clay level (to the next soil type) just pour in a bucket of water and see how long it takes to drain away, it should get faster as you go deeper.

Bear in mind any below ground services such as sewer pipes etc.

I find the longer narrow bladed trench spade better for digging into the clay.

The pebbles can be obtained from your local builders yard and are known as Rejects 40-75m - a 40g poly bag is about £3.00 but bear in mind you may need up to a cu metre which in turn will involve delivery costs and generally come in those 1 tonne bags.

Please be safe and make sure if the person digging is in a hole then the sides are compact and safe - you only need to go about a foot below the clay level.

Don't be tempted to put soil back on top of the pebbles as it will just wash away over time.

If your garden is large and the clay is not that deep then secondary or several soak aways may be better for you. I have one in a garden of about 15 sq metres (soil area) BUT it is around 6 feet deep!

Best of luck!

Steve B

Thanks Steve. Think you're right about the clay. The garden is large (about 130ft long but quite narrow) so I'm guessing we might need several soak aways. Hmm. Might think about getting someone in to do the digging!

Ah, you've moved in further down my street!

When we moved in, my father (soil expert) brought his auger up and we tried to see how far down a layer of gravel or sand was with the idea of digging a soak away. But we got down 7m and didn't find one. We are lucky that there is a slight fall between us and our neighbours - so I have dug a bog garden in the middle of the lawn (filled the raised bed with the soil dug out) and put in french drains under the lawn running down into the bog garden. The bog garden overflows into the neighbours garden at the point where it has historically drained in that direction.

I might have a nosy in the neighbours gardens (sound like a stalker don't I?) and if I manage to spot one without enormous puddles then I might enquire as to how they've resolved it. I'd hate to go to the trouble (or rather pay someone to go to the trouble...) of digging a soak away pit only to discover we need to dig to Australia to have any chance of it working!

Next door dug a soakaway and ended up with a 6' deep pool of water for the children to fall into. Once its full up with water, it just stayed at the watertable height and didn't result in any drainage benefit.

Seems a bit daft just to leave it empty and not fill with pebbles or stones but maybe they were just looking to see whether it would drain first before going to the expense of filling with pebbles rather than backfilling the soil?

Oh well, after another night of rain, the flower beds are once again puddles. When it does stop raining it does drain within a day so I have a little bit of hope that there's something that can be done to improve it.

There are some shrubs and things that appear relatively happy - we've even got a rose bush which appears to be flowering! Bizarre. Don't hold out much hope for ever being able to plant bulbs though - reckon they'd just rot in the ground.

We do raised beds for veg so they don't float off. I have bulbs in tubs, and a few in the 'raised' bits of borders (which are probably 4" above the lawn level). The 'gutter' between the lawn edge and borders has been filled almost to the top for the last 4 weeks here.

Yikes. We're not quite as bad as that. I think raised beds are definitely going to be on the cards - was moseying around at the wild top end if the garden and found bags of unused "horticultural grit" left by previous owners which you supposedly dig into the soil to improve drainage. The right hand flower beds which appear to have been "gritted" don't appear quite as bad as the left hand (ungritted) but it's not really helped much by the looks of it.