I've had my planter box for about three years, Grown veggies and herbs, last year I moved the majority of my veggies into my yard garden... Now with approval of SWMBO I'm coverting the box into a hop bed. Starting with magnum, glacier and goldings, thanks to greatlake hops I'll also be putting in chinook. I went down about a foot with the new 16' 4x4s and sistered them to the existing 4x4s from the garden box. Hopefully I'll have the rest of the posts in this week and the cable ran between them. On a side note... I know hops can grow 20' but even at 15' these posts look massive.