Square Foot Gardening Layout

I've been agenising over what to grow and where in the three number square foot gardening beds that I have planned for next year. They will be 4ft x4ft square and there will be at least three of them, four if I can get them in. 

So my first task was to draw the layout and number the squares. Like the picture at the top right there will be a vertical climbing frame on the side parallel to the boundary wall and this in the top row I have placed climbing plants i.e. Gherkins & Cucumbers, now I'm hoping that cross pollination between them will not be a problem. It's something I will have to look into.

Next Row down some taller plants as in Aubergine & Peppers, however only one of these in a 305mm or 1 ft square leaves too much open land that I want to cover to slow down and shade the weeds, so I'm thinking Radish as they are fast to grow and perhaps even some bunches of spring onions.    

 1  Gherkin (2)  + Radish (8)

 2  Gherkin (2)  + Radish (8) or Possibly Spring Onions ?
 3  Cucumber (2) + Radish (8)
 4  Cucumber (2) + Radish (8) or Possibly Spring Onions ?
 5  Aubergine (1) – Green Knight F1 - Mr Fothergill's + Radish (12)
 6  Pepper (1) – Sweet Lunchbox + Radish (12) or Possibly Spring Onions ?
 7  Aubergine (1)  – Long Purple + Radish (12)  
 8  Pepper (1)  - Summer Salad + Radish (12) or Possibly Spring Onions?
 9  Chard (4) – Fordhook Giant
10 Carrots (16) – Snowman F1 (White Carrots) - D.T.Brown
11 Chard (4) – Bright Lights
12 Carrots (16) – Rainbow Mix - Thompson & Morgan 
13 Lettuce (4) – Little Gem
14 Beetroot (16) - Beetroot Kornett - Mr Fothergill's
15 Lettuce (4) – Amaze - D.T.Brown 
16 Beetroot (16) – Moneta

The idea is to have 3 different mixes of growing mediums and to see what the difference result are

At the moment I'm thinking about 

Bed 1 - Traditional Mels Mix with Coco Grow Coir 

Bed 2 - Traditional Mels Mix with Coco Grow + Coir with added NPK 

Bed 3 - Traditional Mels Mix with Coco Grow Coir with a Natural Grower soil improver and fertiliser.

I have yet to decide what compost I will use in the mix, and I'm researching the price of the Vermiculite, and it appears that many Gardening Centres sell less volume for high prices than you can obtain it for, from companies that sell it for its packing and absorbent properties. A little more desk study and then I will do a sperate post about Vermiculite.  

I will be going into the difference between the different types of Coco Coir products in a later post. 

Proposed layout of the bottom of Plot 1