Need advice putting up pillars in the ground

[OM2]

The wife needs some sort of frame for her plants to grow into. I was thinking of putting up 4 pillars. I wanted some advice on how best to do.

I'm guessing I need to dig down and put concrete down?
Plenty of videos in YouTube.

I thought I would ask here for some advice.

ELSE... would it be a bad idea to build a cube and make sure the base is pretty heavy?

Just looking for ideas.
Thanks.

 

[foxhole]

Screw a trellis frame to a planter box?

 

[conny]

How big/heavy does the frame have to be? Do you want it to be wood or does she just need some support wires for climbers?

More information would get a better response every time.