I have been assembling another semp planter today and thought I would share what I learned from my mistake last year.
I find and buy large planters. I also only plant semps or other perennial plants that need to be outside all winter. I use soda cans in a plastic bag to economise on soil mixture of potting soil and rock garden soil ( shale sand, turkey grit )
Last year I filled this red troth planter and started with a bottom layer of cans and peanuts ( dont use peanuts if you can help it )
I loaded the rest of the troth with rockgarden mix and planted my semps and a alpine.
This spring I could see it was a mistake to plant right away because the soil had settled.
There is no way I want to dig up plants and disturbe the peanuts.
Older and wiser. I let the new Blue Basket planter settle over winter.
I can transplant semps in the spring.Might even make a wishlist for some new ones.
