irrigate garden strips

The best and at the same time inexpensive method has turned out to be sprinkling with a perforated hose. That requires many of these small 3d printed hose holders presented here and some tinkering:
First, get yourself a “gardena” perforated hose, which can be found using the following search term: "gardena hose sprinkler".
Then you need the number of triangle bars over the distance you want to irrigate. Triangular bars are available cheap and pressure impregnated for wooden roofing. Here the 3d-printed brackets will be screwed on later.
Last but not least you have to fix the triangle lines somehow in the ground - I used sheet metal lawn edges for this but you can also use other things like big nails or sticks.