Using real soil for dioramas

First off you need to pinch some of your garden floor – preferably without grass, flowers, trees or patios attached.  

Collecting garden floor is best done in one of those rare phases in Britland called 'a dry spell'. At other times, the garden floor is normally called 'mud'. It's difficult to sieve mud and that is the first stage – to remove the crunchy bits called 'stones'- stop me if I'm being to patronising. DON'T do this near any precision instruments/machines like an airbrush as someone not a million miles away did the first time. What a plonker that person is. 😳
Please ensure there are no occupants residing in your sample. I'm mainly talking about inhabitants visible to the naked eye as the next step will murder millions of microbes – something someone I know previously complained about! Not even the most dedicated Buddhist can go though life without murdering millions of microbes on a daily basis. 

Then you'll need to eat lots of takeaways to leave you with some foil trays which you need to fill no deeper than about inch or it'll still be raw in the middle.
Next you need to cook it. You can use a microwave. If you do, forget about the foil tray step otherwise you'll need to buy a new microwave. I used the oven.
Recipe for cooking garden:
Ensure the house is free from any wives/girlfriends/other-halfs, as cooking bits of garden stinks the kitchen out for quite a few hours. Also, I wouldn't recommend putting it in with the Sunday roast as your din dins may end up tasting sort of earthy. There may be complaints/divorce proceedings.
set cooker to 200% or gas mark – I don't know I use electric, lets say really, really hot.
Cook for 40 – 45 mins.
Ensure it's cool before tasting. Errrr, maybe not. Cooling can take take a surprisingly long time
Serve – preferably with a side salad. 

Originally I sieved the soil even finer after it had cooled (on the right). Technically, this was known as a ‘total waste of time’. Real soil is generally a bit on the lumpy side. 

Initially I tried using the very finely sieved soil for the first few experiments.
I tried using spray adhesive at first, but it bubbled up menacingly and left it looking messy. 

So I tried smearing PVA onto the board and sprinkling the soil dust on top. It ended looking even worse and much too uneven. 

Finally I tried mixing it with PVA with a small amount of previously boiled and cooled water. 

Incidentally, that’s a clear sheet of plastic (from food packaging) I’m mixing it on. This step is very messy. 

Don’t mix it too runny and don’t don't spread it on in thick layers as it'll crack badly as it dries. Having said that, if you want a 'parched earth' effect in your dio, it'll look great. 

Next I tried static grass. Yes I know the grass I used looks hideous – that's why I'm using it in the experiment because it's too hideous to use in a dio. It looks like you can't see any of the soil but the grass looks much better than it does on bare board.  

I had a go at changing the colour of the soil with Tamiya acrylic paint – adding a few drops of black to the PVA. Dark brown would probably have been a better choice. 

The end effect wasn't a particularly realistic colour (the bit on the right), but it proved that changing the tone is possible. I also had a look to see if glossing the dried surface would make it look wetter. It does. 

I still wasn't happy about the look of the soil so I used the soil which wasn't very finely sieved and immediately it looked much better (on the left). 

This is the end result on my second diorama. As the PVA soil was drying I lightly sprinkled some of the dry soil onto the surface and pushed the larger lumps into the surface which I think gives it a bit more variation. 

This is spreading it on another dio which is using foam insulation board as a base. It's still wet here - takes a couple of days to dry usually and gets much lighter when it's completely dry.