[Otis]

I have a saying if you want concrete add sand, if you was very good soil add organic matter.

What does concrete have in it? SAND

But if you feel better using sand than look out for hard ground in clay.

[JayG]

The so-called 'perfect loam' consists of approximately equal quantities of clay, silt, sand and organic matter, so although adding lots of organic matter to soils at either extreme of clay or sand improves their properties and performance considerably, it doesn't change the basic mineral composition of the soil.

That's good enough for most folk - sand can help improve the properties of clay soils but it's nowhere near as simple as tipping a few barrow loads of sand on your plot and hoping for the best. 

+ + +

I still get fragments of glass and pots coming to the surface of my soil after 15 years - it seems almost unbelievable but it's caused by water which collects underneath such objects, freezes, expands and lifts the object up through the soil - it's very slow of course but repeated many times they eventually reach the surface.

[Nobbie]

I have a saying if you want concrete add sand, if you was very good soil add organic matter.

What does concrete have in it? SAND

But if you feel better using sand than look out for hard ground in clay.

Concrete also has water in it, do you advocate not adding water either Before planting my raspberries I added sharp sand and lots of leafmould, seems to have worked a treat. I had concrete before, but not now

[beesrus]

Here's another thought into the mix on a slight tangent, but related.... it's not just the soil condition that produces good food, husbandry, effective land use etc.
No matter what type of soil and it's individual needs, there are many different growing philosophies out there from organic small scale  cottage growing to large scale chemical topped up alluvials and dust bowls on the flat lands, and everything in between. My particular method is also concentrating on the living soil and habitation that leaves no room for what most of us understand as chemical additives. My lovely allotment neighbour goes down the Growmore/glyphosphate route and gets just as good crops to the eye as I do, although she knows now not to offer me any produce. Each to their own. My favourite system is the 1000s of years old small scale self-sustaining fish and silk farmers of SE Asia. That's what I call real thought out productive and sustainable farming. 
 
Apparently us allotmenteers are by far more productive in food per square metre/acre than the big growers. So maybe scale has a part to play in productive growing. Sadly, we aren't given a good deal or press, and regularly get blamed for any ill that befalls the big growers, such as blight. The rent we pay per metre would bankrupt any large scale grower. So, we must be doing something right, chemical or organic.

[Aunt Sally]

A relative of mine in Oz has VERY clay soil. They have had to add gypsum to floculate the clay particles before being able to add organic matter.

[BussinSpain]

The land, just like us needs a good healthy diet.  You can't take out what you don't put in.  Mother nature feeds her land - dead plants, animal droppings etc., natural is best:)

[Snoop]

A relative of mine in Oz has VERY clay soil. They have had to add gypsum to floculate the clay particles before being able to add organic matter.

Agricultural gypsum is fantastic. I'd love some. Only problem is, it's sold here in agribusiness quantities only. This is great advice for anyone who can get hold of it in the right kind of volumes.

[Goosegirl]

I have a saying if you want concrete add sand, if you was very good soil add organic matter.

What does concrete have in it? SAND

But if you feel better using sand than look out for hard ground in clay.

Hi Otis - by sand I didn't mean the fine stuff that builders use, I meant a very coarse one that has almost grit-like particles, or just get some grit and dig it in. My soil is alluvial silt and gets rock hard, but using this has really helped to open it up. As AS says, gypsum is also good but it takes a while to work.

[mobilekat]

One of the things I find most amazing about gardening is the soil.
Where we are now is very sandy- not something I have dealt with before, but it gives a new challenge.
Adding plenty of organic matter, and 'feeding' the soil will help it develop as it is a living organism in my mind.
And the healthier the soil the healthier the plant living in it will be, and thus the better the food I gain from it.
I want to live with a superb ecological system around me, and make my garden into a haven for me, and beneficial wildlife, and to help the 'good guys' you do end up having to tolerate some 'bad guys' as I refuse to use pesticides.
But as has been said it's a continuous evolution as if you try to change things to fast the micro-organisms won't cope.
All good fun, and part of the joy of gardening,

[dugless]

Getting lime and Gypsum in the quantities I need is difficult,  the so called nurseries, garden centres only  stock it in small amounts.
I have found some on the internet though.

[Aunt Sally]

Ebay looks like the cheapest source.

[3759allen]

the more organic matter you add the better in my opinion, for at least the first 5 years (prob double that for you as your soil is cley).

i've heard that you don't need as much organic (although still need some) once the soil condition is very good/ perfect. people that are lucky enough to have perfect soil seem to concentrate more on fertilizers than soil conditioners.

personally i'm using mainly rabbit manure (i have a massive supply now so happy days). i mulch everything while it's growing and turn whats left of this into the soil. i then add more layers of the manure until the ground needs digging over to plant. then mulch around the plants and start the cycle again. all i have found is that you need to allow the the mulch to air to get rid of the urea otherwise it can burn the plants.