Why do my outdoor plants keep dying?

I can’t keep them alive for more than a week, and if I do, they never come into fruition even when it’s their season.

I used to be able to do it, but lately, they just keep dying. What am I doing wrong? I even resorted to a huge greenhouse because I was tired of it, but it looks a bit ugly, so I want regular outdoor garden planters instead….minus dead veg.