If you staple some form of mesh along the 3 walls then you can tie plants to it to keep the back.
Should mean the plants won't over grow your cool tube like they do unrestrained.
If the mesh can't be done then some bamboo stakes in the pots can be used all the same to keep plants back.
Should mean the plants won't over grow your cool tube like they do unrestrained.
If the mesh can't be done then some bamboo stakes in the pots can be used all the same to keep plants back.