This baby jacket is worked in garter stitch.

For the rainbow coloured jacket I used Trekking XXL (4ply sockyarn) colour 415.
I used 75 grams for the jacket but I needed the whole skein to match the both sides.
Size: 0-3 months

For the blue jacket I used Zaubergloeckchen‘s handdyed 6ply sockyarn. I used 130 grams.
Size: one year

You need three buttons, a circular needle and another circular needle or a stitch holder, a tapestry needle for grafting.

gauge: 4 ply sockyarn: 26 sts X 28 garter ridges = 4 inches
6 ply sockyarn: 22 sts X 23 garter ridges = 4 inches