[Tina&Tony]

Our garden soil is heavy clay, there are some established old fruit trees in the garden already - plum and pear..  I'd like to plant new fruit trees but need some advice on how to improve the soil..
I'm going to dig deep and mix in as much composted matter and sharp sand as possible, but I have read that gypsom improves the structure.  How do I use it and can I dig it into the soil before planting?  Will it harm Cherry and plum trees?
Tina

[shaun]

hi tina i have never used gypsum and wouldnt even know where to get it,i would just use lots of manure and leafmould.

[poultrygeist]

Hi Tina,

As far as I've read, it's the addition of lime (which I think Gypsum is a form of/contains) which breaks up heavy clay soil. It binds the smaller clay particles into slightly larger lumps and opens the structure up.

The 'Garden expert' book merely suggests adding lime to counter the acidity of the soil so I can't say how much lime to add but you shouldn't add it within 2 or 3 months of manuring.
If you haven't manured, I would suggest a good covering of hydrated lime and fork it in best you can. No idea how long it takes but presumably it will only improve it, and then keep an eye on the pH of your soil.

Hope this gives you a start.

Rob

[Tina&Tony]

Thanks both for your quick replies -
This is the article I was reading - and Gypsum does sound pretty ideal..  (I think) it just doesnt help answer my question...

"Peter Cox in his book in his 'Dwarf Rhododendrons', published by Batsford in association with the RHS, 1973, recommends gypsum for improving the soil where Azaleas and Rhododendrons are grown.
Another advantage of using gypsum rather than lime for improving clay, again because it's acid, is that it can be used at the same time as ammonia-providing manures and fertilisers, because it won't volatilise the ammonia and waste it. Otherwise it should work in a very similar way to lime, although don't use gypsum if you're actually trying to raise the soil pH and decrease its acidity.
Gypsum, (AKA plaster, plaster of Paris, calcium sulphate) is slightly soluble in water (a similar solubility to lime, roughly about 0.2%). If I had a clay problem and I wanted to keep it acid, I would get a few bags of plaster from a builder's merchant and work that in, assuming it's free from other additives (cement?) that would raise the soil pH. I imagine this would be a lot cheaper than buying a 'clay breaker', knowing most garden centre prices. Builder's plaster is unhydrated, while gypsum is the hydrated form, but that would soon change when it came into contact with damp soil. But, like other clay treatments, little will happen if you just sprinkle it on and stand back. The clay would still have to be broken up and worked with all the other recommended additives (compost, manure, grit, etc.) to get the best results, as with using lime."

Still confused !

[poultrygeist]

aaaarrrr.

So gypsum doesn't actually contain lime but does the same job.

Plaster is gypsum based. But I don't know if it contains other additives which would harm the soil.

Just reading a couple of google links, it should be available at garden centres but, as you say, the clay breakers will be a stupid price.
I would guess a good old fashioned nursery would be able to advise on a supplier.
We used to have a heavy clay garden and I once dug up a big white powdery lump which I discovered was gypsum which had obviously been left out in the rain to harden and must have been used for clay breaking.

Just found this link...

LINK

..which suggests that lime would be better cos it raises the pH which is good if you're growing brassicas, etc. Clay soil is acidic by nature so it will help to make it slightly alkaline.
Also you can buy hydrated lime from builders merchants for abotu £5/25kg bag. Much better value !

R

[ParsnipPete]

Our garden soil is heavy clay, there are some established old fruit trees in the garden already - plum and pear..  I'd like to plant new fruit trees but need some advice on how to improve the soil..
I'm going to dig deep and mix in as much composted matter and sharp sand as possible, but I have read that gypsom improves the structure.  How do I use it and can I dig it into the soil before planting?  Will it harm Cherry and plum trees?
Tina

We have very, very heavy clay, but have managed to plant an orchard over the past twelve years without adding anything to the soil. I wouldn't bother adding anything as the roots spread so far you'd need to literally add tonnes of material to make any improvement. In our veg garden I added five tonnes of sand in one bed (25m2) to make a meaningful difference. I lime every year and only really saw the benefit after five years. Wood ash is the best in my opinion.

[Trillium]

We have such a gypsum product over here called Claybreaker. It's specifically for soil amending, which is what you want to buy (though not necessarily the same brand name). Its now hard to find here simply because of the cost, which was on the high side, but if your soil is so bad then it's worth the price.
However, a lot of us have heavy claggy soils and most of us just work in as much 'good stuff' as we can every year. The plants will do okay the first year in such amended soil as clay does hold more water and nutrients. Yearly additions of humus things will continue to improve the area. I collect bags and bags of leaves in fall that my neighbours are throwing out, empty them into a pile to dry out, then bung them in the plots and rotovate to break them up. Helps no end with aeration and attracting worms. Best of all, people are thrilled to give them free to a better use.

[van connick]

i have just bought ' clay breaker ' from my local agri merchants....£3.50 box...

[Tina&Tony]

Thanks all for your input..
Parsnip pete -  If it was just 'very heavy clay'  I probably would just plant with the normal dose of compost.. but its pure grey clay not a bit of grit or stone in it..  we have dug a pond - unlined - in which the water level hasnt fluctuated any more than the lined ponds in this area!  
I wouldn't even attempt to dig / improve a huge area but if I tried to plant them 'as is' I'd be digging out great lumps of potters clay and have to 'mould it' around the root ball with my fingers to back fill...
Does anyone know if cherry / plum/ pear trees like an acid or alcaline soil? isnt clay normally fairly neutral?

[poultrygeist]

Clay soil is meant to be fairly neutral. Cherry and Plum trees prefer it sllightly acidic so adding rotted manure would do it plenty of favours.

But they will need some sort of drainage. Our last house was built on exactly the same clay soil with a water table about 12-18 inches below the lawn !

We made a couple of raised beds but found that digging in loads of sand followed by loads of compost (old growbags) it did improve enough to grow shrubs.

You could try planting them in a slight raised bed, maybe edged with log roll or something for appearance ?
The subsoil would need digging out and breaking up to at least a couple of feet I would have thought just to avoid the roots sitting in water all the time.
If you can excavate quite deeply and replace with even slightly better draining soil it'd help. Is there an area of your plot with anything better or is it just clay, clay and more clay ?
R

[Tina&Tony]

Hi Poultrygeist..  The garden is in two parts, a long flower border area which I dug deep and mixed with sand and tones of compost, manure and anything else I had to hand - it was back breaking but was well worth it as I have the most lovely mixed borders now..  This opens onto about a third of an acre of what was, when we arrived, a paddock / meadow - chest height and daunting....  It hadn't been touched besides the few fruit trees.  Tony has been working sand in and its now covered in grass,  
The entire area is nothing but the grey clay - waterlogged in winter and deep cracks in summer.. So yes I think I'll have to both dig deep and pile high with added manure, grit etc..  One can but try!!  I've got two cherry trees a pear and a plum to get in as soon as possible..  and its just started sleeting!! - ah well, maybe tomorrow....

[poultrygeist]

Sorry for you. When I dug down to find the water table at our last place, someone had buried a load of gravel, presumably as a sort drainage system about a foot down. The garden sloped from the end down towards the house with a sunken patio about a foot below the lawn for the last 10 feet. The patio had a sump with a pump on a level switch so when it rained, the patio flooded but slowly emptied back up to a drainage ditch at the top of the gardens running along the top ridge.
One side was permanently damp in Summer and semi-pond in winter.
The top end was bone dry due to everythign running down.  :?
Nightmare scenario, and we were thrilled when we moved here to find a good, heavy, free draining soil which had been tended by a gardener for years (but not now! ).
I think you have but the one option which is not only back breaking but expensive too. Good luck with it.  

R

[Trillium]

If you're not up to the backbreaking work, then high raised beds is the only other solution. I say high because your hardpan is fairly impermeable so the roots would have space to spread rather than in regular 1x6 beds.

[Tina&Tony]

Hi Trillium.. If by 'hardpan' you mean the soil surface, its not impermiable at all at this time of year, in fact at the moment the surface is like a mud bath / bog, beneath the surface is like digging potting clay..  In summer it turns into rock!!  Just the joys of clay gardening,,
Tina

[Tinbasher]

Hi Trillium.. If by 'hardpan' you mean the soil surface, its not impermiable at all at this time of year, in fact at the moment the surface is like a mud bath / bog, beneath the surface is like digging potting clay..  In summer it turns into rock!!  Just the joys of clay gardening,,
Tina

You have to dig it out to make any real difference.  I've been in exactly the same boat with pure, never-ending, grey (and even blue) clay.  Try to split the plot into areas and dig out a section at a time.  There's no way you'll get it all done in one season, or several, unless you never do anything else and have access to diging machinery.  Then there's still the problem of getting rid of it, which for me was as big a deal as digging the stuff out in the first place.

I've gone down 30 inches in a bed 27 feet x 8 feet.  I did it in 3 sections of 9' x 8', each one taking a whole autumn/winter, so I had first 9, then 18 and finally 27 feet of cultivated area, which all took going on 4 years to accomplish.  A quick calculation tells me it's 60 cubic yards of clay removed.  A cubic yard of soil is estimated at a ton, whilst wet clay may be twice that weight.  So, maybe 60 -120 tons removed.  When you then consider it has to be dug out and into a barrow (and the deeper you go, the harder this is), then shovelled out of the barrow onto a flatback (into bags is even worse), then shovelled off the flatback onto its final resting place, you realise that in actual fact you've ended up shovelling it all 3 times.  So that could be up to 360 tons of clay moved around by hand. :shock:   I would dread to think of doing it again.  The only quicker way would have been to hire a mini-digger (at about 80 quid a day) and skips (at 130 quid each and you can't have them there forever even at that price) and try to do it all at once - which would have been nigh impossible and anyway cost a fortune.  I relied on a good digging spade, a barrow (I wore one out completely in the process), a flatback van and many visits to the tip.  Even the last option is now closed off as we cannot now go to the tip in anything larger than a car more than once a month, and have to apply for a permit even to do that.  It cuts no ice to say it's purely residential (ie, non-commercial or a paid job) and that a Council official is welcome to visit to check, or that it's 'just' clay and is therefore inert, non-toxic, organic or whatever.  Very luckily for me, I began the job and almost finished it before all these new stringent tipping laws came into force.

Whilst into the job at various stages, it inevitably rains and you are correct in saying that a murky swimming-pool of sorts comes into being, more efficient than any man-made pool, in that it would never drain away until the entire geology of the area changes.  I doubt that the bottom of any of my 9' x 8' pits would have dried out, even via summer evaporation, before more rain arrived to refill them.  Many times I had to spend a good 15 mins baling out gallons, before I could re-commence digging.  Often the water was at mid-shin height, so deep it could be considered dangerous, at least to a small child.  My view is that plant roots would have been almost continually submerged had I not dug as deeply.  Conversely, I can now say that I will probably never have a serious drought on the area as there will always be moisture down there somewhere no matter how hot and dry it is.

In any area larger than the one I dealt with, I would consider raised beds - high ones.  Or you could just dig out a foot and have slightly lower raised beds.  It's still a lot of digging, a lot of weight and a lot of getting rid of.  Leaving all the clay in place and trying to improve by addition of stuff is in my view futile in the short-term.  You need tons of grit sand even to vaguely notice and feel an improvement.  Even then, any treading on the area compacts the surface so much that you've taken three steps forward and two steps back.  It would have taken me years and years to notice any improvement as well as dozens of tons of additions, which apart from the cost would have brought the level halfway up my gable end and covered the windows!