Drainage Issues
robmarsh79
Posts: 5
We are very new to gardening in general so bear with us and apologies if we ask stupid questions 
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We have always had drainage problems in our garden since we moved in three years ago. It's a relatively new build so we suspect the quality of soil is pretty bad and full of rubble. The local soil is quite high clay content in this area too.
A couple of months ago we got new lawn put down and as we were trying to improve drainage we also got the gardeners to replace the top foot or so of soil with better quality top soil. it doesn't seemed to have helped at all though as we still get pooling of water on the surface after rain.
How would be best prepare the borders to improve drainage so we can start to plant trees and plants that may not like wet soils.
Thanks in advance
Posts
Muck and grit should help but it's better to choose plants that do well in the soil you have
In the sticks near Peterborough
Thanks for the quick reply. one of the problems we have at the minute is that everything that we want to plant all states that it needs 'well drained' soil, and ours is anything but well drained!
Obviouslay having plants/trees in the borders would improve drainage as you would expect them to take up a lot of the water, but would it be well drained after that? And would it be too wet initially for anything to even get started growing in?
The other idea we had was to dig down about a metre just in the borders and replace with even better quality too soil and make sure it's less compacted. But if the border is surrounded by hard compacted clay soil are we. It just creating a bigger trough for the water to collect in?
Thanks again for reading
Hopefully the builders didn't dump a load of large rubble or excess hardcore in your garden and compact it to save on waste disposal costs
Hardcore is good for drainage but if compacted and in conjunction with clay soil, you may always be faced with drainage issues.
Digging the borders deep - down to 2-3ft or more and removing any compacted rubble, clay soil, then aerating ithe subsoil would be a good start. Replacing with loose hardcore underneath, sharp sand and new topsoil on top will help the grass drain too. Having a deep vertical lawn edge... 6 inches or more where the grass meets the borders will help.
The above is a major task and if you buy plants that like damp conditions, it would save time and money but your lawn will likely be blighted forever with moss and other issues associated with excess moisture if something isn't done.
If you have solid clay once you go down a couple of feet, it is probably that and not the topsoil that is causing the drainage problem. At least, that's my experience.
Obviously though if you can improve the top couple of feet,that will assist anyway.Mowtastic spells it out.
Your suspicion that you could be creating a sump if you just do a small area is correct.
Easiest thing would probably be going raised bed route.
I have a 70 foot birch tree sucking up water but it doesn't help in the winter.
Last edited: 30 April 2017 15:36:21
**UPDATE** we're following the advice on digging down and seeing what we get. The more we dig the more we are thinking we might stop at two feet! But we're determined to get to a metre
Picture to follow, but essentially we are running into more and more compacted clay soil.
It looks like it's just clay and more clay....no compacted hardcore. There doesn't appear to be a high water table as you'd be stood in water.
This is good & bad news as it doesn't mean getting rid of tonnes of hardcore that could be creating a sump... but the clay itself will act as as a sump; catch 22.
You may be limited by the clay subsoil to what it is possible to grow. Improving the soil by digging in coarse sand or ballast as well as plenty of organic material such as compost, composted tree chippings or manure will help but could be a massive task.
The raised borders as Candre mentioned, with a deep vertical edge cut into lawn where it joins the borders will help channel the water away from the lawn. Plants that thrive in clay soils will need to be considered. Here's a page that may help:
https://www.rhs.org.uk/advice/Profile?pid=305
Some trees and shrubs may help extract the water. Weeping Willow, Dogwood, Alders and River Birch are some examples but will need to be maintained to stop them becomming huge and detrimental to your house.
Thanks again for eveyone's fantastic feedback.
Looking at that list, the trees we were hoping to put in there were Himalayan Birch and a Roman and both are on there which is positive at least.
Another option I was looking at is that there is a drain on the corner of the garde. I was thinking I could put a pipe in the soil to direct the water down that, however without completely gutting the current drain and changing fittings the pipe would only be about a foot deep under the soil. I was hoping to pipe it away much deeper than that.
We will keep digging and post some pics again of progress. Thanks again people, all advice much appreciated
Yes putting in drainage would fix the issue.
Big job though.