First of all, it's another way to recycle cardboard.

The main benefit is that, when you plant seeds in this pot and it grows bigger than the pot, you can easily plant the pot and seedling together inside the yard or a bigger pot without needing to remove the seedling from its first pot.

That eliminates the danger of hurting the seedling.

Step 1: Things Needed

Stapler
Utility knife or scissors
Ruler
Pen
Non-glossy cardboard

I used a glossy cardboard here myself, just because I didn't have a non-glossy one at hand when making this instructable.

Glossy cardboards decompose slower and might leach toxins/chems into the soil, do not use them for this project.

Step 2: Measure and Mark

The pot dimensions will be 5x5x7 centimeters.

Grab the ruler and pen, and mark three rectangles on the cardboard as in the picture, with these dimensions:
- Two 19x5 parts
- One 25x3 part

Step 3: Cutting

Using the knife or scissors, carefully cut the cardboard at the markings.

Step 4: Folding

Fold the parts at these points:

For two 19x5 parts:
Fold them so a 5cm section is placed in the center.

For the 25x3 part:
Simply fold it each 5cm until the end of it.

Step 5: Attaching Parts

Using the stapler, attach the parts like the picture.

You should get a star shape and a double end opened cube (which will act as a brace)

Step 6: Assembling

Carefully apply the brace on the star so the pot keep its shape.

Now your pot is ready to use.

Step 7: Using It

Just pour some compost inside it and plant your seed(s).

Once the seedling(s) become larger than the pot, you should plant the whole pot inside soil in a bigger container, and after burying it, carefully remove the brace to make the pot loose for roots to grow between the gaps and reach the outside soil.

Thanks to the bacteria, the pot itself will be decomposed after awhile, and roots will easily penetrate it and even feed on it.