Need advise on building a large planter box please!
Hello! This spring we are planning on building a rather large planter box to run the length of our back fence (50ft long by 2.5ft high and 4ft wide). We are using 2inx10inx16ft pressure treated boards with 4x4 posts; we plan on cutting the boards in half and placing a post every 8ft which will be facing the outside. We are planting about 14 to 16 6ft tall Emerald Green Arborvitae in the planter box to provide some extra privacy.
My questions are these:
Because the box will be so large, do we need to add any sort of supports in the box for extra stability?
What type of drainage do we need if any? (There will not be a bottom to this box, just dirt)
Is there anything else we should do to ensure this planter box lasts a long time?
Also, will emerald greens do good in a planter box?
Any other advice is greatly appreciated! Thanks!