Seeking help identifying my soil type

I hope i have the right section of the forum but this is my first post!

I live on the mendips and therefore have learnt that (through reading and experimentation) that i have limestone bedrock and VERY alkaline sandy ish soil.

 But with the recent heavy persistant rain recently, my novice ability in identitfying my soil type as limestone sandy was brought into question when i was out gardening on my alpine rockery area and found that due to me tramping all over it the soil was more clay like when compacted. Also, whilst the first 6-8 inches deep was relatively free draining, beyond that it was "mud pie central" and like some one had buried a bucket of water just there!

A couple of additional clarifying points about my small garden - 1. i have covered 95% of the garden with ground cover matting and blue slate (due to an appalling lawn and weeds nightmare when we moved in so this might be affecting water levels due to less evaporation??. 2. Property was built in 1997 so whilst it isnt a new build it seemed to have that type of soil (builders leftovers) ....maybe?!

Thanks for reading!

There's always a top soil layer over subsoil, with added pockets of rubble if its  a new build. Your's sound like it might be compacted which isn't unusual if a garden is used by everyone other than a gardener who would probably define borders with edging and start digging.

Monty discovered a border that had a hard pan of soil eighteen inches down that was stopping plants thriving on GW a few years back. His advice was to take out all the plants, double dig to break up the pan, adding grit and compost for better drainage and then replant. You might want to start small

I think you may have a point with compact soil/subsoil...i have to admit to being a perfectionist generally speaking and so i have to keep telling myself that i'm not gonna get everything right first time plus i tend to go for immediate gratification in my gardening so i couldn't resist digging over the soil, adding peat free compost and planting alpines fairly quickly when i got going march time without thinking if adding compost which would help enrich the soil but also increase  water retention was the right thing to do.

Only time will tell i suppose but it is trial and error at the end of the day.

What confused me as well was whilst my soil felt gritty and crumbly ... i could roll it into a ball or sausage shape....is it more important to know the pH and drainage properties of a soil than its definite sandy/clay/chalky etc?

It's very useful to know the ph of your soil but personally I don't think its absolutely essential unless you are thinking of growing specific plants/veg. What is essential is your environmental observations.

Remember that alpines like a lot of grit because they hate to have their necks in the wet (which is why gravel is used) and very free draining soil so they don't have soaking wet feet. I'm no expert on Alpines or any other gardening subject, just a keen reader and gardener and as much as I can sympathise with your impatience to see results, those results won't be long term unless you take care of your soil.

In my experience, gardening is not so much about making plants grow but stopping plants from dying by providing their natural habitats as much as possible, keeping on top of pests and diseases and being good to the soil. 

P.S two soil tests I saw recently from Monty and Jo on GW programs. Firstly Monty squeezed a handful of soil to test its texture, but then he threw the lump on the floor and if it break up easily, its not too heavy. Secondly, Jo put some soil in a jam jar, adding water and the lid, then gave it a good shake and left it a few days. the clay sinks to the bottom, the middle section is the sand/grit, them the water and the floaty bits are the organic matter. You can get some clue as to the condition of your soil this way

My house was built seven years ago. The garden has had 12 " of topsoil laid on top of compressed clay / limestone that I guess was compacted by heavy machinery using what was to be my garden as a route to deliver loads of bricks etc.. to houses being built at the same time. If I want to plant anything substantial I have to take a 5 foot long, very heavy crowbar, heavy duty mattock, pick axe, and spade, and it's hard graft. When we get long periods of heavy rain like now large puddles form in certain areas. One summer I lost several climbing roses that had just been planted that winter due to them being flooded. When planting a few weeks later I still found that, in some areas, once I got 12" down the hole kept filling with water.

In long periods of drought my young trees and shrubs really struggled to start with. But now I reckon most have found a way to get some roots through the hardpan to keep them going in drought conditions.