Gardening is a great hobby but there are some disadvantages :

ground is low
weeds grow in the alleys
it can become untidy and unsightly
slugs go everywhere

You can find some responses to those issues with "Square Foot Garden"

It is easy to build them yourself for less that 80 Eur per unit.

Step 1: The Material

For one unit you need :

12 planks "autoclave". I used 36 mm thick and 120 cm length they are 14.5 mm large.
4 aluminium angles 50 mm x 50 mm and 45 cm length (it is better to get them one or two centimeter longer that 3 times the board width, so that the square does not touch the ground)
24 stainless steel screws (for example 4.5x60 mm sparx)
2 terrace planks 128 cm x 15 cm
some plastic strip to protect foundations 60 cm width 5+ meters length (we call it here in Europe "Diba")

Step 2: Prepare the Corners

Drill some holes in the angles for the screws.

Look at the picture, you have to drill two in the middle of one corner's side and two to the ends of the other corner's side. Make a template with a board to do a neat job.

Enlarge the holes a little bit on the top so that the screw does not stay out.

Step 3: Assemble the Boards

Assemble the planks in a staggered arrangement.

Place the angle so that it is aligned with the top of the square and exceeds 2 cm at the bottom.

Step 4: Protect the Wood

Unroll the plastic protection inside and recover the top and the bottom

Fix it with some stapples.

Step 5: Implantation

The first one is the more difficult .. after you can make more .. and align them. (I did 15 of them)

Lay the corners on some pavements.

Fix them in the meanwhile you fill them with garden soil.

Do not put any plastic at the bottom, just lay it on the ground. You can put a wire mesh if you are afraid from animals coming from the bottom.

Prepare some sheaths for the irrigation passing from one square to the other.

Step 6: Top Frame

Add a frame to the top.

Choose a durable wood like terrace exotic wood.

Cut the 15 cm plank in two in the length direction to get 7.5 cm x 128 cm planks.

Assemble it with wood glue, tighten with a strap. Add some stapples at the corner.

Align and fix them at the top with 2 vertical screws on each side.

Step 7: Anti Slug

Buy some aluminium nets and cut bands of a couple of centimeters.

Fix them below the top frame and fold them down.

This system prevents the slugs to go in your garden.

I must admit that slugs are very braves and some of them still manage to get in !

You can improve the system by filling a small channel with a mix of salt and grease but the mixture has to be renewed frequently to remain efficient..(see last picture)