After your first partial play trough, you learn pretty quick where to dash off to get all the good crops to plant right away (tatos , mut fruit, and corn (because those 3 make adhesive). Won't spoil anything - just say within easy run distance of Sanctuary is a farm you can pick a ton of tatos, and while not a short journey - not a long one either - a level 1 char can easily make it to another farm to get all the mut fruit and corn you need/
The slower, but easier way, is just spend a few caps with the first merchant you run into. Likely trashcan carla. She has every now and then a few plantable seeds. All you need is 1 if you want to take the time. Plant, harvest, now you have 2 plants - harvest for 2 seeds, now you have 4 plants, etc.
Personally, other than for cosmetic and aesthetic view, there is no real reason to plant anything other than the 3 plants above, since those are what make adhesives.