Extreme Clay Soil - page 2

These are some emails that I exchanged with a lady in a garden in Lancashire with a number of major problems (the garden that is!)

Question:  Last year we moved into a property with 2/3rds of an acre of paddock surrounded by fields. Last summer was very dry and the land was rock hard.  In July, we hired a digger and driver to excavate a pond and discovered that there was a few inches of top soil after which it turned to clay and was still clay four foot down.

We also had the digger man dig some large deep pits which we filled with top soil and planted 12 decent sized trees  (cherries, rowans, silver birch, etc) which cost several hundred pounds.   Now it is winter and we find that the tree pits are totally waterlogged.  The land itself is very wet although there is no surface water accumulating  except in the tree pits themselves. 

We have a septic tank but when we purchased the property was advised that it overflows into the septic tank of the neighbouring property which we understand then overflows into a nearby stream so I do not believe this is contributing to the wet ground problem.  Basically it seems that the clay is causing the ground to be waterlogged but when I have researched field drains/soakaways, etc, it seems to be a bit of a minefield and I understand not necessarily the answer to the problem.  It appears that improving the condition of the clay by lots of digging and mulching, etc, is the answer but with 2/3rds of an acre what is the best (and most economical) way to tackle this problem.

Is there a mechanical method of dealing with this effectively? Apparently rotovators are not a good idea as they don't go deep enough and are often ineffective in the hands of the novice.  I would like to have a nice lawn, raised beds, trees, shrubs, paths, etc, as quickly as is reasonably practical and which won't die because they are virtually sitting in water over winter.  Incidentally, would it be possible to save the waterlogged trees - what would I need to do to manage this?  Any advice you can give me would be very welcome.

Advice:

Now it is winter and we find that the tree pits are totally waterlogged. 

Yes they would be, it happens like that on clay soil, you've dug below the winter water table and inadvertently made a series of sumps. 

I would like to have a nice lawn, raised beds, trees, shrubs, paths, etc, as quickly as is reasonably practical and which won't die because they are virtually sitting in water over winter. 

With 2/3rds of an acre, you need to work with the soil and not try to change it wholesale. Drainage of such an area can be quite a complex problem, particularly if there is a stream nearby, you'd need to get an expert in really to take a look and give advice, all this and the work involved would be potentially expensive, though as you say there is no standing water probably not necessary.  

Blessings - clay is very nutrient-rich soil and when plants get established, they will be better off than in most other soils.  Lawn - shouldn't be a problem at all, grass will grow on all kinds of soils and the top-soil over clay means that it's far less likely to ever dry out and get scorched.  Raised beds - no problem, fill them with top-soil brought in.  Paths - shouldn't be a problem as there's no standing water.  

Trees, shrubs and other plants, see here

Rather than try to change lots at once, tackle smaller areas one at a time,  digging is better than rotavating, but in time even surface organic matter  will be dragged into the soil by the worms.  As for the trees, are they still alive? Try breaking a few buds open to see. The rowans are more tolerant of wet conditions, but the cherries and birches less so. They might survive regardless, but the only way you'll know this is by trying and if they don't - well too late. The answer is simply to move them somewhere they will like to be instead, do you have a better area around? somewhere at the top of a slope that they could be moved to? The only other alternative is really to put them into some large containers or raised bed so the roots aren't rotting in the wet. The cherries will be the most sensitive to wet.  Take a look around the surrounding area, what kinds of trees are there? If there are similar ones to any of yours, then they are probably the ones to leave where they are.  I'd also suggest getting a landscaper or designer in as it could well save you a lot of money in the long run and there's nothing like specific advice for a specific area.

Question:  I have approached a couple of local landscape gardeners, both have suggested installing drains and leading them to a large sump hole at the bottom corner of the garden. It appears some of the farmer's field from which our patch was purchased by the previous owners of our house is inclined to drain in our direction, no doubt exacerbating our water problem.

We explored the possibility of draining into the septic tank but as suspected, the general opinion is that it won't be able to cope and to dig a ditch or install a pipe to link with the nearest existing drainage ditch it would need to be 10' deep at its lowest point to accommodate the fall of the land - this is cost prohibitive - even if the farmer would give his permission - so I don't feel inclined to tread those particular boards.

Terraces have been suggested, formed by using large limestone blocks and backfilling which along with the drains, 280tons of top soil and lawning with seed is around £7k for the cheaper quote. I don't have a clue whether that is a realistic proposition and would value your expert opinion regarding whether you think the proposal is reasonable both from a resolution and cost perspective. At least it might tidy up the land and make it reasonable to work with because at the moment it is a liability which I feel devalues the property.   

I can put tree, shrubs and beds in myself once the basics are done.   Perhaps Groundforce would come and work one of their 48 hour miracles ( as if !!!)   Incidentally, we lifted the trees last weekend and I think they are still alive. Hopefully they will survive whilst we get our act together.

Advice:  Terraces - well they'd work, but I don't like them except on very steep slopes, cost seems about what I'd expect. If you are considering spending that amount, I'd seriously consider getting in a designer as a contractor alone isn't necessarily going to come up with the best solution.

Many designers will give a first consultation for less than the price of one of your large trees probably.  This might seem a cop-out, but I can't really give you an answer without seeing the plot in the "flesh". If you were local and I saw it, I'd come up with a few ideas myself. I'd then get a guy I've worked closely with in the past to take a look, he's a landscaping contractor and is very good at realizing what can and can't be done easily. 

He'd tell me / the client what could be done with ease and what could be done with more effort / cost / another contractor. We'd then decide to proceed down one of his / my routes. From what you've told me, I'd proceed with either working with the land, or get in a designer or two to give you some possibilities.  Before you do any of this though, sit down and write a list of what you'd like from the garden. You might despair about the soil and the clay, but looking from the property point of view, all most people want is a patio / deck area, something to look pretty from there and maybe a kids play area which at its simplest could be just a level area of lawn.

Question:  I have not contacted the landscape gardeners awaiting your reply.  I can see the logic of getting in a garden designer.  Presumably the ground work (ie, drainage) would need to be sorted regardless but as you suggest a garden designer might have more imagination and it seems it would cost a lot less than I imagined so I think I'll try that if I can find one in my area.

Thanks again for your very useful input.  When I have turned the lifeless plot into Kew Gardens I will send you a photo.