All sorts of factors can contribute to a waterlogged, soggy garden and these are the 10 most common causes I have found
;
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Heavy sustained rainfall can cause underground springs to change direction.
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Compacted soil combined with the mixing of subsoil and topsoil when the house was built is a very
common reason for soggy spongy lawns.
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Clay soil. You can't blame it all on the builder, it's more likely the house and garden have been
built on clay (easily recognised because the surface cracks up when it is dry). Not easily avoidable however, as great swathes of the UK consist of clay soil.
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The garden is lower than neighbouring gardens or at the bottom of a hill. Water flows downwards and
unless it has been dealt with upstream by installing a drainage system to catch or divert the water, is naturally going to be a problem downstream. It's not really your neighbour's fault that
this is happening.
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Structures like swimming pools, home extensions you or neighbours have added can all cause gardens to
flood. Anything with deep footings can divert water.
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Uneven lawn or garden surfaces. On clay and other water retentive soils, the flow of water through the soil is very slow made worse by
dips in the surface allowing water to puddle and flood during heavy rain.
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Hard landscaping. The increasing use of impermeable materials to construct car parking, driveway and
patios is a problem. Rainwater that should be soaking into the ground runs across the hard impermeable surface into the property and gardens below it. If you are unlucky enough to live next
to (and lower than) a tarmac or concrete parking area, you could try asking the culprit to install a French drain on their side to catch and divert the water away
from your property.
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Is it the Water Table? Some water table information here.
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Gutters and down-pipes not connected into the drainage system (or blocked) instead discharging onto
the garden or patio. Always connect the down-pipe into a drain.
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Diverting water into your property. If your neighbour has recently installed a garden
drainage system check that it is not terminating at the boundary between your properties and discharging water into your garden.
A lot of time and money can be spent trying to trace the water source, leading to disputes with neighbours, the surveyor and builder who built the extension, the landscape gardener who
installed your paving and retaining wall without considering the effect on soil drainage.
Use my D.I.Y garden drainage guide together with the
information on this page and my other linked pages to install a simple and low cost gravel drainage system to drain your soggy garden.
Lower down this page I have also included some common DIY mistakes that won't dry out your garden and lawn.
What DIY garden drainage system will work to dry out a waterlogged garden and
lawn?
A gravel drain trench system (French Drain) installed below the surface, solves most garden drainage problems. Ever since the Romans
used them to solve drainage problems, not much has changed, perforated plastic pipes (holes at the top or bottom, depends who you ask !) came and went, French drains still work.
Why are they are called French drains? Although stone drains go back the Ark, they are
actually named after an American, Henry French a 19th-century judge,gardener and farmer.
Can I fix a waterlogged garden and soggy
lawn problem myself ?
Yes with the right tools, including a trench spade, trench shovel, spirit level and a trench hoe that are preferably made for trenching and sturdy
enough to lift clay. (I have featured the tools I use, further down this page)
You will need to enlist the help of a few fit friends and neighbours and if you have access, hire a
digger or set aside few weekends digging trenches in clay soil, lugging a few tons of gravel
into your garden and getting rid of an equal amount of clay, what goes into French drains must come out first.
Installing French drain style garden drainage is not rocket science, It's mostly common sense (water will only flow downhill) and hard labour, digging trenches, taking tons of clay out and wheelbarrowing the
same amount of gravel back in.
Following these D.I.Y. garden and lawn drainage tips will help. Depending on how your garden slopes the different DIY methods described here will
stop water logging.
Herringbone drainage works for lawns and
gardens that are
waterlogged over the whole area.
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Mark out the main trench from the highest part of the lawn, to the
lowest.
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Mark the side trenches to connect to the main drain, forming a
herringbone pattern. The side drains join the main drain at a 45 degree angle.
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Space side drains at 10 ft intervals for clay soil and 25 ft intervals
for loamy soil
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Dig out the trenches to at least 18 inches deep, saving about 6" off
the best clay free topsoil to backfill.
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Line the trench with landscape fabric to keep earth out of the gravel
to allow water to percolate through easily.
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Shovel coarse 20 ml gravel onto the landscape fabric leaving 4 to 5
inches to back fill and fold the fabric over the top of the gravel.
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Shovel or rake the topsoil you have saved back into the trench,
slightly over filling to allow for settling.
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At the lowest end of the main trench dig out a soak away at least 4 ft
deep and link the main drain to the centre of the soak away. Bear in mind if you hit clay when digging out the soak away it's not going to work and you will need to look at either connecting
into the surface water drain system or installing a sump and
pump
Single French drain.
Used to drain water away from a wet, soggy or waterlogged part of your garden to a soakaway or drain.
Slope the French drain to carry the water down to its destination. Dig the trench across the waterlogged area and then towards the soak
away. This type of drain need only be about 6" wide and 12" deep. Before filling with gravel, line the trench with landscape fabric to keep earth out of the gravel to allow water to
percolate through easily. Shovel 5 to 7 inches of 20 ml coarse gravel onto the landscape fabric. Wrap the fabric over the top of the gravel and top up with soil.,
Soakaway drainage
trench
For lawns that are level, not on clay, not
compacted and water lays on the surface, a soak away trench could work. Dig a trench about 2ft deep and 2ft wide along the length of the lawn. Line the trench and partly fill the trench with
about 12in of clean brick rubble, then 8 ins of gravel and top up with soil. Soakaways won't drain away in heavy clay soils. Worth aerating the surface first, might just be
compacted!
For any type of drainage system that is installed below the surface of a lawn or garden to work to full
capacity, the surface needs to be kept aerated.
Bog area & water feature. You could try making the most of waterlogged areas in gardens and lawns by installing
a bog garden area
filled with colourful bog plants, I have listed a few here garden ponds.
Happy user
Just completed the drainage on my lawn using your diy guide, must say it was simple to follow still hard work, but what a difference, my boys can play on
the lawn again, and I did save a lot of money. I found the gravel calculator really useful, ended up with a bit left over but probably my calculation.
Thanks again and for the chat on the phone (well worth a tenner)
Jason. Leeds
name and address supplied